A customer wants to estimate the average delivery time of apizza from the local pizza parlor. Over the course of a few months,the customer orders 28 pizzas and records the delivery times. Theaverage delivery time is 20.06 with a standard deviation of 5.271.If the customer estimates the time using a 95% confidence interval,what is the margin of error?

Question 1 options:

	1) 2.0439
	2) 1.6967
	3) 0.9961
	4) 0.6215
	5) 2.0405

Question 2 (1 point)

You own a small storefront retail business and are interested indetermining the average amount of money a typical customer spendsper visit to your store. You take a random sample over the courseof a month for 15 customers and find that the average dollar amountspent per transaction per customer is $86.485 with a standarddeviation of $15.8647. Create a 99% confidence interval for thetrue average spent for all customers per transaction.

Question 2 options:

	1) ( 74.291 , 98.679 )
	2) ( 82.389 , 90.581 )
	3) ( 83.508 , 89.462 )
	4) ( -74.291 , 98.679 )
	5) ( 74.413 , 98.557 )

Question 3 (1 point)

The owner of a local phone store wanted to determine how muchcustomers are willing to spend on the purchase of a new phone. In arandom sample of 9 phones purchased that day, the sample mean was$338.73 and the standard deviation was $19.7969. Calculate a 95%confidence interval to estimate the average price customers arewilling to pay per phone.

Question 3 options:

	1) ( -323.513 , 353.947 )
	2) ( 336.424 , 341.036 )
	3) ( 332.131 , 345.329 )
	4) ( 323.513 , 353.947 )
	5) ( 323.803 , 353.657 )

Question 4 (1 point)

Suppose you work for Fender Guitar Company and you areresponsible for testing the integrity of a new formulation ofguitar strings. To perform your analysis, you randomly select 40'high E' strings and put them into a machine that simulates stringplucking thousands of times per minute. You record the number ofplucks each string takes before failure and compile a dataset. Youfind that the average number of plucks is 6,886.7 with a standarddeviation of 117.85. A 99% confidence interval for the averagenumber of plucks to failure is (6,836.2, 6,937.2). From the optionlisted below, what is the appropriate interpretation of thisinterval?

Question 4 options:

	1) We are 99% confident that the proportion of all 'high E' guitarstrings fail with a rate between 6,836.2 and 6,937.2.
	2) We are 99% confident that the average number of plucks tofailure for all 'high E' strings tested is between 6,836.2 and6,937.2.
	3) We cannot determine the proper interpretation of thisinterval.
	4) We are 99% confident that the average number of plucks tofailure for all 'high E' strings is between 6,836.2 and6,937.2.
	5) We are certain that 99% of the average number of plucks tofailure for all 'high E' strings will be between 6,836.2 and6,937.2.

Question 5 (1 point)

The owner of a local golf course wants to determine the averageage of the golfers that play on the course in relation to theaverage age in the area. According to the most recent census, thetown has an average age of 23.44. In a random sample of 26 golfersthat visited his course, the sample mean was 30.63 and the standarddeviation was 8.771. Using this information, the owner calculatedthe confidence interval of (25.84, 35.42) with a confidence levelof 99%. Which of the following statements is the bestconclusion?

Question 5 options:

	1) We are 99% confident that the average age of all golfers thatplay on the golf course is greater than 23.44
	2) We are 99% confident that the average age of all golfers thatplay on the golf course is less than 23.44
	3) The average age of all golfers does not significantly differfrom 23.44.
	4) The percentage of golfers with an age greater than 23.44 is99%.
	5) We cannot determine the proper interpretation based on theinformation given.

Question 6 (1 point)

Researchers at a metals lab are testing a new alloy for use inhigh end electronics. The alloy is very expensive to make so theirbudget for testing is limited. The researchers need to estimate theaverage force required to bend a piece of the alloy to a 90 degreeangle. From previous tests, the standard deviation is known to be34.632 Newtons. In order to estimate the true mean within a marginof error of 9.703 Newtons with 99% confidence, how many sampleswould need to be tested?

Question 6 options:

	1) We do not have enough information to answer this question sincewe were not given the sample mean.
	2) 95
	3) 90
	4) 84
	5) 85

Question 7 (1 point)

A pharmaceutical company is testing a new drug to increasememorization ability. It takes a sample of individuals and splitsthem randomly into two groups. After the drug regimen is completed,all members of the study are given a test for memorization abilitywith higher scores representing a better ability to memorize. Those28 participants on the drug had an average test score of 28.396 (SD= 4.142) while those 26 participants not on the drug had an averagescore of 40.736 (SD = 5.24). You use this information to create a90% confidence interval for the difference in average test score.What is the margin of error? Assume the population standarddeviations are equal.

Question 7 options:

	1) 1.28060017
	2) 1.662
	3) 2.145
	4) 1.67468915
	5) 2.106

Question 8 (1 point)

In a consumer research study, several Meijer and Walmart storeswere surveyed at random and the average basket price was recordedfor each. It was found that the average basket price for 8 Meijerstores was $132.15 with a standard deviation of $24.701. 11 Walmartstores had an average basket price of $156.97 with a standarddeviation of $19.049. Construct a 99% confidence interval for thedifference between the true average basket prices (Meijer -Walmart). You can assume that the standard deviations of the twopopulations are statistically similar.

Question 8 options:

	1) (-50.62, 0.98)
	2) (-53.85, 4.21)
	3) (-34.84, -14.8)
	4) We only have the sample means, we need to know the populationmeans in order to calculate a confidence interval.
	5) (-650.61, 600.97)

Question 9 (1 point)

Independent random samples are taken at a university to comparethe average GPA of seniors to the average GPA of sophomores. Givena 95% confidence interval for the difference between the trueaverage GPAs (seniors - sophomores) of (0, 1.13), what can youconclude?

Question 9 options:

	1) We are 95% confident that the difference between the two sampleGPAs falls within the interval.
	2) We are 95% confident that the average GPA of seniors is greaterthan the average GPA of sophomores.
	3) There is no significant difference between the true average GPAfor seniors and sophomores.
	4) We do not have enough information to make a conclusion.
	5) We are 95% confident that the average GPA of seniors is lessthan the average GPA of sophomores.

Question 10 (1 point)

The owner of a local golf course wants to estimate thedifference between the average ages of males and females that playon the golf course. He randomly samples 24 men and 21 women thatplay on his course. He finds the average age of the men to be37.722 with a standard deviation of 7.091. The average age of thewomen was 32.214 with a standard deviation of 5.243. He uses thisinformation to calculate a 99% confidence interval for thedifference in means, (0.436, 10.58). The best interpretation ofthis interval is which of the following statements?

Question 10 options:

	1) We are certain that the difference between the average age ofall men and all women is between 0.436 and 10.58.
	2) We are 99% confident that the difference between the averageage of the men and women surveyed is between 0.436 and 10.58
	3) We do not know the population means so we do not have enoughinformation to make an interpretation.
	4) We are 99% sure that the average age difference between allmales and females is between 0.436 and 10.58.
	5) We are 99% confident that the difference between the averageage of all men and all women who play golf at the course is between0.436 and 10.58

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