Answer:
38.911≤p≤41.089
Step-by-step explanation:
The formula for calculating confidence interval for a population mean us as shown below;
CI = xbar ± Z×S/√N where;
xbar is the sample mean = 40
Z is the z score at 95% confidence interval = 1.96
S is the standard deviation = 5
N is the sample size = 81
Substituting this parameters in the formula we have;
CI = 40±1.96×5/√81
CI = 40±(1.96×5/9)
CI = 40±(1.96×0.556)
CI = 40±1.089
CI = (40-1.089, 40+1.089)
CI = (38.911, 41.089)
The 95% confidence interval for the population mean is 38.911≤p≤41.089
Answer:
38.9 ≤ U ≤ 41.1
Step-by-step explanation:
Mean, m = 40; standard deviation, α = 5; Confidence limit, U = 95% or 0.95
N = 81
The standard error, α(m) = α/√(N) = 5/√81 =5/9
Using table: 0.95 = 0.0379
Z(0.95) = 2 - 0.0379 = 1.9621 or 1.96
Hence, confidence interval = { m - 1.96(α/√N) ≤ U ≤ m +1.96(α/√N)}
But, 1.96(α/√N) = 1.96 X 5/9 = 1.96 X 0.56 = 1.1
(40 - 1.1 ≤ U ≤ 40 + 1.1)
∴ the confidence interval = 38.9 ≤ U ≤ 41.1
34% of working mothers do not have enough money to cover their health insurance deductibles. You randomly select six working mothers and ask them whether they have enough money to cover their health insurance deductibles. The random variable represents the number of working mothers who do not have enough money to cover their health insurance deductibles.
Required:
Construct a binomial distribution using n= 0.6 and p=0.34
Answer:
solution below
Step-by-step explanation:
The question says 6 working mother's were selected so n = 6 not 0.6
We are expected to find
P(X = 0,1,2,3,4,4,6)
1. When x = 0
6C0*(0.34)⁰*(0.66)⁶
= 1 *1* 0.827
= 0.0827
2. When X = 1
6C1*(0.34)¹*(0.66)⁵
= 6 x 0.34 x 0.252
= 0.2555
3. When X = 2
6C2*(0.34)²*(0.66)⁴
= 15 x 0.1156 x 0.1897
= 0.3289
4. When x = 3
6C3*(0.34)³*(0.66)³
20 x 0.039304 x 0.2875
= 0.2599
5. When X = 4
6C4*(0.34)⁴*(0.66)²
= 15 x 0.01336 x 0.4356
= 0.8729
6. When x = 5
6C5*(0.34)⁵*(0.66)¹
= 6 x 0.0045 x 0.66
= 0.01782
7. When x = 6
6C6*(0.34)⁶*(0.66)⁰
1 x 0.0015 x 1
= 0.0015
Bob Nale is the owner of Nale's Texaco GasTown. Bob would like to estimate the mean number of litres (L) of gasoline sold to his customers. Assume the number of litres sold follows the normal distribution with a standard deviation of 18 L. From his records, he selects a random sample of 18 sales and finds the mean number of litres sold is 56.
a. What is the point estimate of the population mean? (Round the final answer to the nearest whole number.)
The point estimate of the population mean is
litres.
b. Develop a 80% confidence interval for the population mean. (Round the final answers to 3 decimal places.)
The 80% confidence interval for the population mean is between
and
.
c. Interpret the meaning of part (b).
If 100 such intervals were determined, the population
mean
would be included in about
intervals.
Answer:
a
The point estimate of the population mean is [tex]\= x = 56[/tex]
b
The 80% confidence level is [tex]50.57 < \mu < 61.43[/tex]
c
There is 80% confidence that the true population mean lies within the confidence interval.
Step-by-step explanation:
From the question we are told that
The sample size is n = 18
The standard deviation is [tex]\sigma = 18 \ L[/tex]
The sample mean is [tex]\= x = 56[/tex]
Generally the point estimate of the population mean is equivalent to the sample mean whose value is [tex]\= x = 56[/tex]
Given that the confidence interval is 80% then the level of significance is mathematically represented as
[tex]\alpha = 100 - 80[/tex]
[tex]\alpha = 20 \%[/tex]
[tex]\alpha = 0.20[/tex]
Next we obtain the critical value of [tex]\frac{\alpha }{2}[/tex] from the normal distribution table
The value is [tex]Z_{\frac{ \alpha }{2} } = 1.28[/tex]
Generally the margin of error is mathematically evaluated as
[tex]E = Z_{\frac{\alpha }{2} } * \frac{\sigma }{\sqrt{n} }[/tex]
=> [tex]E = 1.28 * \frac{18 }{\sqrt{18} }[/tex]
=> [tex]E = 5.43[/tex]
Generally the 80% confidence interval is mathematically represented as
[tex]\= x - E < \mu < \= x + E[/tex]
=> [tex]56 - 5.43 < \mu < 56 + 5.43[/tex]
=> [tex]50.57 < \mu < 61.43[/tex]
The interpretation is that there is 80% confidence that the true population mean lies within the limit
PLEASE SOLVE THE ABOVE PROBLEM you’ll get 43 POINTS
heya friend
0.2
0.2**10/10
=2/10
in 2/10 2 and 10 are integers
and 10 is not zero
so it is sacrificed
hope this helps u
Answer:
0.2
0.2**10/10
=2/10
in 2/10 2 and 10 are integers
10 is not 0
Step-by-step explanation:
On a map 1 cm represents 4.5km. What is the actual distance between two towns which are 4cm apart on the map?
Answer:
18km
Step-by-step explanation:
1cm:4.5km/4cm then get the answer as 18km
1 cm represents [tex]4.5[/tex] km. To find the actual distance between two towns that are 4 cm apart on the map, we can use the scale ratio.
Since 1 cm represents [tex]4.5[/tex] km, we can calculate the actual distance by multiplying the map distance with the scale ratio. Map distance: 4 cm Scale ratio: 1 cm represents [tex]4.5[/tex] km Actual distance = Map distance × Scale ratio Actual distance[tex]= 4 cm × 4.5[/tex] km/cm Actual distance[tex]= 18 km[/tex]
Therefore, the actual distance between the two towns is18 [tex]18[/tex] km. Using the given scale, 1 cm on the map corresponds to[tex]4.5[/tex]km in reality. As the towns are represented as 4 cm apart on the map, the actual distance between them is [tex]18[/tex]km.
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What is the intersection of the given lines? AB←→and EB←→ point B BE←→ point A point E
Answer:
point B
Step-by-step explanation:
The names of the lines, AB and BE, tell you that point B is on both lines.
Point B will be the point of intersection.
Answer:
point b
Step-by-step explanation:
i took the test and got it right
Find the largest number apart from 840 that is a multiple of 24 and a factor of 840.
Answer:
168
Step-by-step explanation:
first, split both 840 and 24 into there primes.
840=2×2×2×3×5×7
24=2×2×2×3
therefore any multiples of 24 must have those factor.
so, factors of 840 that are multiples of 24 are
2×2×2×3=24
2×2×2×3×5=120
2×2×2×3×7=168
2×2×2×3×5×7=840
there the answer is 168
Find all real solutions of the equation: x 2 + 3x − 10 = 0
Answer: x=8/3 or x= 2.6666....
Step-by-step explanation:
[tex]2+3x-10=0[/tex]
[tex]2-10=-8[/tex]
[tex]3x-8=0[/tex]
add 8 on both sides
[tex]3x-8+8=0+8[/tex]
[tex]3x=8[/tex]
divide 3 on both sides
[tex]x=\frac{8}{3}[/tex]
Answer:
8/3
Step-by-step explanation:
2 +3x + 10 = 0
2-10 +3x = 0
-8 + 3x = 0
3x = 8
x = 8/3
Use the following cell phone airport data speeds (Mbps) from a particular network. Find the percentile corresponding to the data speed 4.9 Mbps.
0.2 0.8 2.3 6.4 12.3 0.2 0.8 2.3 6.9 12.7 0.2 0.8 2.6 7.5 12.9 0.3 0.9 2.8 7.9 13.8
0.6 1.5 0.1 0.7 2.2 6.1 12.1 0.6 1.9 5.5 11.9 27.5 0.6 1.7 3.3 8.3 13.8 1.3 3.5 9.8
14.6 10.1 14.7 11.8 14.8
Answer:
Thus percentile lies between 53.3% and 55.6 %
Step-by-step explanation:
First we arrange the data in ascending order . Then find the number of the values corresponding to the given value. Then equate it with the number of observations and x and then multiply it to get the percentile. n= P/100 *N
where n is the ordinal rank of the given value
N is the number of values in ascending order.
The data in ascending order is
0.1 0.2 0.2 0.2 0.3 0.6 0.6 0.6 0.7 0.8 0.8 0.8 0.9 1.3
1.5 1.7 1.9 2.2 2.3 2.3 2.6 2.8 3.3 3.5 5.5 6.1 6.4 6.9 7.5 7.9 8.3 9.8 10.1 11.8 11.9 12.1 12.3 12.7 12.9 13.8 13.8 14.6 14.7 14.8 27.5
Number of observation = 45
4.9 lies between 3.3 and 5.5
x*n = 24 observation x*n = 25 observation
x*45= 24 x*45= 25
x= 0.533 x= 0.556
Thus percentile lies between 53.3% and 55.6 %
What percent of the area underneath
this normal curve is shaded?
Answer:
The area shaded is 95%
Step-by-step explanation:
The total area under the curve is 100 percent
1 standard deviation away from the mean is 68 percent
2 standard deviations away is 95 percent
The area shaded is 95%
The percentage of the shaded area underneath this normal curve is 95% because it lie within two (2) standard deviations of the mean.
What is the 68-95-99.7 rule?The 68-95-99.7 rule is also referred to as the empirical rule or the three-sigma rule and it can be defined as a shorthand which is used in statistics to determine the percentage of a population parameter that lie within an interval estimate in a normal distribution curve.
Basically, the 68-95-99.7 rule states that 68%, 95%, and 99.7% of the population parameter lie within one (1), two (2), and three (3) standard deviations of the mean respectively.
This ultimately implies that, the percentage of the shaded area underneath this normal curve is 95% because it lie within two (2) standard deviations of the mean.
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Which is the graph of g(x) = (0.5)x + 3 – 4?
Answer:
Graph (A)
Step-by-step explanation:
Given question is incomplete; find the question in the attachment.
Given function is g(x) = [tex](0.5)^{x+3}-4[/tex]
Parent function of the given function is,
f(x) = [tex](0.5)^{x}[/tex]
When the function 'f' is shifted by 3 units left over the x-axis, translated function will be,
h(x) = f(x+3) = [tex](0.5)^{x+3}[/tex]
When h(x) is shifted 4 units down, translated function will be,
g(x) = h(x) - 4
g(x) = [tex](0.5)^{x+3}-4[/tex]
g(x) has a y-intercept as (-4).
From the given graphs, Graph A shows the y-intercept as (-4).
Therefore, Graph A will be the answer.
Answer:
The Answer A is correct
Step-by-step explanation:
I took the edg2020 test
Jake’s dad is 6 more than 3 times Jake’s age. The sum of their ages is 42 . Find their ages. Use whole numbers.
Answer: Jake is 9 and his dad is 33.
Step-by-step explanation: 9x3=27+6=33 9+33=42
Answer:
Jake is 9 and Jake's dad is 33
Step-by-step explanation:
To solve this we need to create a equation where D is the age of Jake's dad and J is the age of Jake
J+D=42
3J+6=D
Solve by substitution
Two faces of a six-sided die are painted red, two are painted blue, and two are painted yellow. The die is rolled three times, and the colors that appear face up on the first, second, and third rolls are recorded. (a) Find the probability of the event that exactly one of the colors that appears face up is red.
Answer:
12/27
Step-by-step explanation:
Step 1
We find all the total number of possible outcomes of rolling two faces of a six-sided die are painted red, two are painted blue, and two are painted yellow.
Where
R = Red
B = Blue
Y = Yellow
RRR, BBB, YYY, RBY, RYB, YBR, YRB, BRY, BYR, BBY, BBR, YYB, RRY, RRB, BYB, BRB, YRY, YBY, RYR, RBR,YRR, BRR, RBB, RYY, BYY,YBB, YYR
We have 27 Total outcomes for this 6 faced die
Step 2
The event that exactly one of the colors that appears face up is red.
RBY, RYB, YBR, YRB, RBB, RYY, BBR,
BRB, BRY, YRY, BYR, YYR
Total number of Possible outcomes where EXACTLY one of the colours that appears face up is red = 12
The probability of the event that exactly one of the colors that appears face up is red = Number of possible outcomes/ Total number of outcomes
= 12/27
Reading a Tape Measure
Measure the green bar using the provided image of a tape measure
Answer:
3 inches
Step-by-step explanation:
The green bar reaches all the way to the 3 on the ruler, and each number represents an inch.
Which of the following statements is TRUE about the stepwise selection procedure?
A. The stepwise selection procedure uses Adjusted R-square as the "best" model criterion.
B. Backward stepwise procedure and forward stepwise procedure would end up with the same "best" model.
C. The "best" model determined by the stepwise selection method is the same model as what would be selected by complete search but stepwise method is usually faster.
D. Different choices of alpha limits for variable selection may end up with different final models.
Answer:
A. The stepwise selection procedure uses Adjusted R-square as the "best" model criterion.
Step-by-step explanation:
Stepwise regression is a model which uses variables in step by step manner. The procedure involves removal or inclusion of independent variables one by one. It adds the most significant independent variable and removes the less significant independent variable. Usually stepwise selection uses R-square or Mallows Cp for picking the best fit.
Find the area of the region enclosed by the curves x=3y^2, x=0, and y=2
Answer:
8
Step-by-step explanation:
Hello,
[tex]x=3y^2<=>y=\sqrt{\dfrac{x}{3}} \ \ for \ x\geq 0[/tex]
And for y = 2, x = 3 * 2 * 2 = 12 so first, let's compute
[tex]\displaystyle \int\limits^{12}_0 {\sqrt{\dfrac{x}{3}}} \, dx =\dfrac{1}{\sqrt{3}} \int\limits^{12}_0 {\sqrt{x}} \, dx\\\\=\dfrac{1}{\sqrt{3}} \left[ \dfrac{2}{3}x^{3/2}\right]_0^{12}\\\\=\dfrac{1}{\sqrt{3}} *\dfrac{2}{3}*12*\sqrt{12}\\\\=\dfrac{2*12*2*\sqrt{3}}{3*\sqrt{3}}\\\\=2*4*2=16[/tex]
The area which is asked is 12*2 - 16 = 24 - 16 = 8
Hope this helps.
Do not hesitate if you need further explanation.
Thank you
Using integrals, it is found that the area of the region enclosed by the curves in the interval is of 27 units squared.
In this problem:
The curve is [tex]x = 3y^2[/tex], hence the integral is relative to y.The lower limit is when x = 0, hence [tex]0 = 3y^2 \rightarrow y = 0[/tex].The upper limit is when y = 2.Then, the integral for the area is:
[tex]A = \int_{0}^{2} 3y^2 dy[/tex]
[tex]A = y^3|_{y = 0}^{y = 3}[/tex]
[tex]A = 3^3 - 0^3[/tex]
[tex]A = 27[/tex]
The area of the region enclosed by the curves in the interval is of 27 units squared.
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Select the correct graph.
Answer:
Graph 1
Step-by-step explanation:
The only graph that could be possible would be graph 1.
As you can see the function x = 2t - 4 is linear, and the only graph that consists of a linear line would be the first graph.
will rate you brainliest
Answer:
A
Step-by-step explanation:
f(x)→g(x)
(0, 0) → (3, -4)
Therefore it increases it x-axis from 0 to 3
And decreases in y-axis from 0 to -4
Point A is at (2, -8) and point C is at (-4, 7).
Find the coordinates of point B on AC such that the ratio of AB to BC is 2:1.
Answer:
(-2, 2)
Step-by-step explanation:
Given:
Point A is at (2, -8) and point C is at (-4, 7)Difference of coordinates:
Δx = 2 - (-4) = 6Δy = - 8 - 7 = - 15The ratio of AB to AC is 2:1. So:
AB = 2*AC/3 and BC = AC/3Then coordinates of point B should be 2/3 from the point A:
x = 2- 6*2/3 = 2 - 4 = -2y = - 8 - (-15)*2/3 = -8 + 10 = 2So point B has coordinates of (-2, 2)
(x+1)(x−1)(x−5)=0 HELP
Answer:
x³ - 5x² - x + 5
Step-by-step explanation:
(x+1)(x-1)(x-5) = 0
fisrt step:
(x+1)(x-1) = x*x + x*-1 + 1*x + 1*-1 = x² - x + x - 1 = x² - 1
then:
(x+1)(x-1)(x-5) = (x²-1)(x-5)
(x²-1)(x-5) = x²*x + x²*-5 -1*x -1*-5 = x³ - 5x² - x + 5
Consider the following sample data: 12, 13, 7, 5, 15, 18. Which one of the following represents the value of the standard deviation?
A. 11.67
B. 4.89
C. 2.52
D. 23.87
Answer:
Standard deviation= 4.46
B) 4.89 is the nearest answer
Step-by-step explanation:
Standard deviation √variance
Variance= (summation (x-mean)²)/n
Mean= summation of numbers/total
Mean =( 12+13+ 7+5+15 18)/6
Mean= 70/6
Mean= 11.67
Variance=(( 12-11.67)²+(13-11.67)²+ (7-11.67)²+(5-11.67)²+(15-11.67)²+ (18-11.67)²)/6
Variance= (0.1089+1.7689+21.8089+44.4889+11.0889+40.0689)/6
Variance= 119.3334/6
Variance= 19.8889
Standard deviation= √variance
Standard deviation= √19.8889
Standard deviation= 4.46
HELP ASAP PLS :Find all the missing elements:
Answer:
a ≈ 1.59
b ≈ 6.69
Step-by-step explanation:
Law of Sines: [tex]\frac{a}{sinA} =\frac{b}{sinB} =\frac{c}{sinC}[/tex]
Step 1: Find c using Law of Sines
[tex]\frac{6}{sin58} =\frac{c}{sin13}[/tex]
[tex]c = sin13(\frac{6}{sin58})[/tex]
c = 1.59154
Step 2: Find a using Law of Sines
[tex]\frac{6}{sin58} =\frac{a}{sin109}[/tex]
[tex]a = sin109(\frac{6}{sin58} )[/tex]
a = 6.68961
A committee of 3 is to be chosen from 4 girls and 7 boys.Find the expected number of girls in a committe, if numbers are chosen at random
Answer: There is only 1 girl.
Step-by-step explanation:
As you can see the probability of choosing a girl is 4/11 out of the whole people which is 7 boys and 4 girls. And the same way the probability of choosing a boy is 7/11 which is almost doubled the amount of girls. So to think about it, there will be more boys than girls if there is a random selection because the boys chances of getting picked is high.
Lynn estimates roof jon 1500,bo estimates 2400. What's the ratio to lynn to bo
Answer:
5:8
Step-by-step explanation:
If I understand your question correctly, we have 1500/2400=15/24=5/8, so we have Lynn:Bo is 5:8, however, in the future please be more clear.
What is "estimates roof jon"? And, instead of saying "ratio to lynn to bo" say "What is the ratio of the estimates?" or whatever you're asking. If this answer is wrong, you only have yourself to blame.
To divide a whole number or decimal by 10, move the decimal point
place(s) to the left.
Answer:
you simply have to move one left. It thats decimal you can simply remove one zero
Answer:
You just have to move to the left once
Step-by-step explanation:
In the figure above, ABCD is a parallelogram
with AB = BE = EC. If the area of right triangle
BEC is 8, what is the perimeter of polygon
ABECD?
The perimeter is 21.66
The figure is something like the one that is in the image below:
We want to find the total perimeter of the polygon ABECD
This will be:
AB + BE + EC + CD + DA
Remember that for a triangle rectangle of catheti A and B, the area is given by:
A*B/2
We know that the sides of the triangle rectangle are:
BE, EC, BC.
Because BE = EC, these can not be the hypotenuse of the triangle, then the catheti are BE and EC
Knowing that the area of the triangle rectangle is 8, we can write:
EC*BE/2 = 8
and EC = BE = x
x^2/2 = 8
x^2 = 8*2 = 16
x = √16 = 4
Then the two catheti of the triangle rectangle are 4 units long.
EC = 4
BE = 4
and we know that:
AB = BE = EC
then:
AB = 4
and because this is a rectangle, we also have:
DC = AB = 4
now we want to find the last side of the figure, AD,
Which we already know is equal to the hypotenuse of the triangle.
Remember the Pythagorean's theorem, which says that the sum of the squares of the catheti is equal to the square of the hypotenuse.
Both catethus are equal to 4, then we have:
H^2 = 4^2 + 4^2 = 32
H = √32 = 5.66
then:
DA = 5.66
Now we have:
AB = BE = EC = DC = 4
DA = 5.66
Then the perimeter is:
AB + BE + EC + CD + DA
4 + 4 + 4 + 4+ 5.66 = 21.66
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How do "Combinations" work? What's the formula to solve this equation?
[tex]_nC_k=\dfrac{n!}{k!(n-k)!}\\\\\\_{34}C_{34}=\dfrac{34!}{34!0!}=1[/tex]
In general, [tex]_nC_n=1[/tex]
help pls:Find all the missing elements
Step-by-step explanation:
Using Sine Rule
[tex] \frac{ \sin(a) }{ |a| } = \frac{ \sin(b) }{ |b| } = \frac{ \sin(c) }{ |c| } [/tex]
[tex] \frac{ \sin(42) }{5} = \frac{ \sin(38) }{a} [/tex]
[tex]a = \frac{5( \sin(38))}{ \sin(42) } [/tex]
[tex]a = 4.6[/tex]
[tex] \frac{ \sin(42) }{5} = \frac{ \sin(100) }{b} [/tex]
[tex]b= \frac{5( \sin(100))}{ \sin(42) } [/tex]
[tex]b = 7.4[/tex]
In Littletown, the probability that a baseball team goes to the city playoffs is 0.30. the probability that the team goes to the state playoffs given that the team goes to the city playoffs is 0.20.
THIS IS THE COMPLETE QUESTION BELOW;
In Littletown, the probability that a baseball team goes to the city playoffs is 0.30. the probability that the team goes to the state playoffs given that the team goes to the city playoffs is 0.20.
What is the probability that a randomly selected team from Littletown goes to the city and state playoffs?
A. 0.10
B.0.50
C. 0.66
D. 0.06
Answer:
OPTION D is correct
d)0.06
the probability that a randomly selected team from Littletown goes to the city and state playoffs is [tex]0.06[/tex]
Step-by-step explanation:
The probability that a baseball team goes to city playoffs is 0.30.
P(baseball team goes to city playoffs)=0.30
The probability that the team goes to state playoffs given that the team goes to the city playoffs is 0.20.
P(team goes to state playoffs given that the team goes to the city playoffs)=0.20
From our knowledge of set, we know that
P(A | B)= P(A ∩ C)/P(C)
where A= city playoffs
B= state playoffs
P(State play off | city play off)=0.20
P(State play off ∩ city play off)/P(city play off,)=0.20
P(State play off ∩ city play off)/0.30 =0.20
P(State play off ∩ city play off)= 0.30 × 0.20
= 0.06
Hence,the probability that a randomly selected team from Littletown goes to the city and state playoffs is 0.06
The number of weekly hours spent on a smart device varies inversely with the person's age. If a 20-year-old person spends 52 hours on their smart device each week, how many hours does a 50-year-old person spend on their smart device?
Answer:
20.8 hours
Step-by-step explanation:
Given that hours (h) varies inversely with age (a) then the equation relating them is
h = [tex]\frac{k}{a}[/tex] ← k is the constant of variation
To find k use the condition h = 52 when a = 20, thus
52 = [tex]\frac{k}{20}[/tex] ( multiply both sides by 20 )
1040 = k
h = [tex]\frac{1040}{a}[/tex] ← equation of variation
When a = 50, then
h = [tex]\frac{1040}{50}[/tex] = 20.8 hours
Assume that females have pulse rates that are normally distributed with a mean of μ=73.0 beats per minute and a standard deviation of σ=12.5 beats per minute. Complete parts (a) through (c) below.a. If 1 adult female is randomly selected, find the probability that her pulse rate is less than 76 beats per minute.b. If 25 adult females are randomly selected, find the probability that they have pulse rates with a mean less than 76 beats per minute.c. Why can the normal distribution be used in part (b), even though the sample size does not exceed 30?A. Since the mean pulse rate exceeds 30, the distribution of sample means is a normal distribution for any sample size.B. Since the distribution is of individuals, not sample means, the distribution is a normal distribution for any sample size.C. Since the distribution is of sample means, not individuals, the distribution is a normal distribution for any sample size.D. Since the original population has a normal distribution, the distribution of sample means is a normal distribution for any sample size.
Answer:
a. the probability that her pulse rate is less than 76 beats per minute is 0.5948
b. If 25 adult females are randomly selected, the probability that they have pulse rates with a mean less than 76 beats per minute is 0.8849
c. D. Since the original population has a normal distribution, the distribution of sample means is a normal distribution for any sample size.
Step-by-step explanation:
Given that:
Mean μ =73.0
Standard deviation σ =12.5
a. If 1 adult female is randomly selected, find the probability that her pulse rate is less than 76 beats per minute.
Let X represent the random variable that is normally distributed with a mean of 73.0 beats per minute and a standard deviation of 12.5 beats per minute.
Then : X [tex]\sim[/tex] N ( μ = 73.0 , σ = 12.5)
The probability that her pulse rate is less than 76 beats per minute can be computed as:
[tex]P(X < 76) = P(\dfrac{X-\mu}{\sigma}< \dfrac{X-\mu}{\sigma})[/tex]
[tex]P(X < 76) = P(\dfrac{76-\mu}{\sigma}< \dfrac{76-73}{12.5})[/tex]
[tex]P(X < 76) = P(Z< \dfrac{3}{12.5})[/tex]
[tex]P(X < 76) = P(Z< 0.24)[/tex]
From the standard normal distribution tables,
[tex]P(X < 76) = 0.5948[/tex]
Therefore , the probability that her pulse rate is less than 76 beats per minute is 0.5948
b. If 25 adult females are randomly selected, find the probability that they have pulse rates with a mean less than 76 beats per minute.
now; we have a sample size n = 25
The probability can now be calculated as follows:
[tex]P(\overline X < 76) = P(\dfrac{\overline X-\mu}{\dfrac{\sigma}{\sqrt{n}}}< \dfrac{ \overline X-\mu}{\dfrac{\sigma}{\sqrt{n}}})[/tex]
[tex]P( \overline X < 76) = P(\dfrac{76-\mu}{\dfrac{\sigma}{\sqrt{n}}}< \dfrac{76-73}{\dfrac{12.5}{\sqrt{25}}})[/tex]
[tex]P( \overline X < 76) = P(Z< \dfrac{3}{\dfrac{12.5}{5}})[/tex]
[tex]P( \overline X < 76) = P(Z< 1.2)[/tex]
From the standard normal distribution tables,
[tex]P(\overline X < 76) = 0.8849[/tex]
c. Why can the normal distribution be used in part (b), even though the sample size does not exceed 30?
In order to determine the probability in part (b); the normal distribution is perfect to be used here even when the sample size does not exceed 30.
Therefore option D is correct.
Since the original population has a normal distribution, the distribution of sample means is a normal distribution for any sample size.
