A sample of 16 overweight people take a new reducing pill for 6 weeks and have a mean weight loss of 20 lbs . The standard deviation is 8 lbs . You may assume that the distribution is normal . a) Find a 95 % confidence interval for the mean weight loss . b) If the same information was found using a sample of 50 , how would that cffect the length of the confidence interval

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A sample of 16 overweight people take a new reducing pill for 6 weeks and have a mean weight loss of 20 lbs . The standard deviation is 8 lbs . You may assume that the distribution is normal .

a) Find a 95 % confidence interval for the mean weight loss .

b) If the same information was found using a sample of 50 , how would that cffect the length of the confidence interval the standard

standard deviation of S.16.
) Find a 99% confidence interval for the mean price of regular gasoline.
b) If we had used a 95% confidence level, how would that have effected the
length of the confidence interval?
c) Based on your answer in part a) of this problem do you accept or reject
the Retailers claim that the mean price is $2.18 Please explain your
answer.
4) A sample of 16 overweight people take a new reducing pill for 6 weeks
and have a mean weight loss of 20 lbs. The standard deviation is 8 Ibs.
You may assume that the distribution is normal.
a) Find a 95% confidence interval for the mean weight loss.
b) If the same information was found using a sample of 50, how would that
cffect the length of the confidence interval
5) The mean score for the Verbal SAT in the USA is M =480, the standard
deviation is6- 90 A sample of 100 students in a school district had a sample
meanX 512.
At the 1 % significance level is the data suflicient to show that the SAT
scores are higher in this district
Transcribed Image Text:standard deviation of S.16. ) Find a 99% confidence interval for the mean price of regular gasoline. b) If we had used a 95% confidence level, how would that have effected the length of the confidence interval? c) Based on your answer in part a) of this problem do you accept or reject the Retailers claim that the mean price is $2.18 Please explain your answer. 4) A sample of 16 overweight people take a new reducing pill for 6 weeks and have a mean weight loss of 20 lbs. The standard deviation is 8 Ibs. You may assume that the distribution is normal. a) Find a 95% confidence interval for the mean weight loss. b) If the same information was found using a sample of 50, how would that cffect the length of the confidence interval 5) The mean score for the Verbal SAT in the USA is M =480, the standard deviation is6- 90 A sample of 100 students in a school district had a sample meanX 512. At the 1 % significance level is the data suflicient to show that the SAT scores are higher in this district
Expert Solution
Step 1

4)

a)

The sample mean = 20.

Sample standard deviation, s is 8.

The sample size, n is 16.

From the EXCEL, using the formula, =T.INV.2T(0.05,15), the critical value is  2.1314.

The 95% confidence interval mean is calculated as follows:

CI=x¯±tsn   =20±2.1314×816   =20±4.2628   =15.7372,24.2628

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