In a survey, 24 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $42 and standard deviation of $2. Construct a confidence interval at a 98% confidence level.

Answer:

The 98% confidence interval for the mean amount spent on their child's last birthday gift is between $40.98 and $43.02.

Step-by-step explanation:

We have the standard deviation for the sample, which means that the t-distribution is used to solve this question.

The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 24 - 1 = 23

98% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 23 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.98}{2} = 0.99[/tex]. So we have T = 2.5

The margin of error is:

[tex]M = T\frac{s}{\sqrt{n}} = 2.5\frac{2}{\sqrt{24}} = 1.02[/tex]

In which s is the standard deviation of the sample and n is the size of the sample.

The lower end of the interval is the sample mean subtracted by M. So it is 42 - 1.02 = $40.98.

The upper end of the interval is the sample mean added to M. So it is 42 + 1.02 = $43.02.

The 98% confidence interval for the mean amount spent on their child's last birthday gift is between $40.98 and $43.02.

On January 2, 2008, the American Idol website (www .americanidol) conducted an online poll that asked respondents which contestant they liked best among six former contestants. To become part of the sample, respondents simply clicked on a response. Of the 941,434 responses to this poll, 55% voted for Clay Aiken. We can conclude that _________________________________ .
a. the sample is too small.
b. a fraction of the millions of people who watched the TV show to draw any conclusion.
c. most Americans prefer Clay Aiken out of those former contestants.
d. the poll uses voluntary response, so the results tell us little about the population of all adults.

41. A pair of shoes was originally priced at
$90. After two successive discounts of
10% and 5%, what was the final price?
(1) $72.90
(2) $75.00
(3) $76.95
(4) $78.25
(5) $80.40
of 30 and a pe-

What is the solution to this system of equations?

a - b + c = -6
b - c = 5
2a - 2c = 4

A) 2

B) -1

C) -3

D) 1

30 35 23 22 28 39 21 Population 2 45 49 15 34 20 49 36 Use this data to find the 90% confidence interval for the true difference between the population means. Assume that both populations are normally distributed. Step 3 of 4 : Calculate the margin of error to be used in constructing the confidence interval. Round your answer to six decimal places.

Determine the domain and range of the relation. *​

What is the equation of the line in the following graph?

I NEED HELP ON MATH PLS

radius is 21 5/8 incercepted by 5Pi/6? What is arc lenght?

An advertiser goes to a printer and is charged $36 for 80 copies of one flyer and $46 for 242 copies of another flyer. The printer charges a fixed setup cost plus a charge for every copy of single-page flyers. Find a function that describes the cost of a printing job, if xx is the number of copies made.

I need helpppp please I don’t understand this question at alll

PLEASE HELP THIS IS DUE ASAP!!!!!!!!!!

The number line shows the record low temperatures for four states.. what is the difference, between the low temperature in Hawaii and the low temperatures In south Dakota
A -70°F
B -46°F
C 46°F
D 70°F​

Question 1 of 10
What is the value of n?
144
O A. 36
O B. 23
O C. 95°
D. 590

The admission fee at amusement park is $1.50 for children and $4 for adults on a certain day 355 ppl entered the park and the admission fees collected a total 970,000 dollars how many children and how many adults were admitted?

Before an election, combining the results of 12,625 polls with 14,491,635 samples in total, it shows that 6,413,959 responders (44.3%) say they will vote for the first candidate and 6,134,272 responders (42.3%) say they will vote for the other candidate. Assume a binomial model Binomial(n,p) of the polls for the first and second candidates, where p is the percentage of the votes to the first candidate and n is the total number of votes to the first candidate or the second candidate. Suppose we are interested in whether the first candidate wins more than half of the votes to the first and second candidates:
H0: p = 0.5 v.s. H1: p > 0.5
(a) Compute the test statistics of the generalized likelihood ratio test. Is this test a uniformly most powerful test?
(b) Use Wilks' theorem to compute the critical value of the generalized likelihood ratio test under α = 0.05 level. Make a decision.
(c) Another test has test statistics p - po/√po(1 - po)/n, where po = 0.5. Compute the p-value of this test using the central limit theorem and make a decision. Assume the significance level α = 0.05.
(d) If the second candidate wins the election, comment on possible problems in this statistical analysis.

Leena is arranging 3 different books in a row on a shelf. Create a sample space for the arrangement of a detective story (D), a mystery story (M), and a comic book (C).

Source
StylesNormal

Find the Antilog of 547.840​

I need help finding what U stand for

Simply this rational expression.
URGENT! PICTURE INCLUDED

áp dụng quy tắc khai phương 1 tích hãy tính

find the missing length indicated​

Please help brainliest will be given

Complete the equation describing how
x and y are related.
x
-1
5
0 1 2 3 4
3 8
V 2
13
18
23
28
y = 5x + [?]
Enter the answer that belongs in [?].

build and sketch 2x2+7x+6)

Please help me to find out the answer

If 2L of solution needs to be administered through an IV over 24hours, then how many mililitres of solution needs to be provided per hour, rounded to two decimal places?

Find the sum of the geometric sequence.
1, 1/2, 1/4, 1/8, 1/16.

4 + 1n(x-1)=3 solve for x

What is the conversion factor from meters to centimeters?
10,000 meters per centimeter
100 meters per centimeter
100 centimeters per meter
10,000 centimeters per meter

Savannah used 2 quarts of paint on a summer project. She still had 5.
quarts of paint left when she was finished. How much paint did Savannah
have at first?
la cloud

When is it appropriate to use the​ two-sample t-methods instead of the one sample​ t-methods? Choose the correct answer below. A. Use the​ two-sample t-methods when a sample was taken from each of two populations​ (i.e. two groups being​ compared) and the population standard deviations are not known. Use the​ one-sample t-methods when a sample was taken from one population. B. Use the​ two-sample t-methods when a random sample was not taken. Use the​ one-sample t-methods when a random sample was taken. C. Use the​ two-sample t-methods when the conditions for inference using the​ one-sample t-methods​ aren't satisfied. D. Use the​ two-sample t-methods when the population standard deviation is known. Use the​ one-sample t-methods when the population standard deviation is not known.