Question

Maria is a waitress at Dreck burgers. She wants to estimate the average amount each table leaves for a tip. A random sample of 5 groups was taken and the amount they left for a tip (in dollars) is listed below:

$11.00

$7.00

$7.00

$5.00

$10.00

A) What is the mean of the data?

B) What is the standard deviation of the data? (Use two decimal places)

C) Find a 95% confidence interval for the average amount left by all groups. (*round to the nearest cent*)

< <

D) If the sample size were larger, with everything else remaining the same, would the Margin of Error Increase or Decrease?

• Increase
• Decrease

E) If the Confidence level were 90% instead of 95%, would the range (size) of the Confidence Interval be Larger or Smaller?

• Larger
• Smaller

Answer 1

A) Mean = 8

B) standard deviation = 2.45

C)

95% confidence interval is 4.96 < u < 11.04

D) If the sample size were larger, with everything else remaining the same, would the Margin of Error Decrease.

E) 90% confidence interval is given by

here 90 % confidence interval for population mean is given by 5.67 < 10.33

Range of 95% CI = 11.04 - 4.96 = 4.08

Range of 90% CI = upper limit - lower limit

= 10.335 - 5.665 = 4.65

As we can seen when we used 90% confidence interval instead of 95% Confidence interval .it reduces the range of confidence interval.

Answer : smaller

PL??