Question

Questions 25-26: A company claims that their fridges have an average of 22 gallons of useable space inside. You want to see whether they are cheating the consumer. To test this claim, you take a sample of 50 fridges and find the sample mean and sample standard deviation to be 21.2 and 3.0, respectively.

25. What would be the appropriate alternative hypothesis? (Hint: is the customer being cheated if the usable space is too little, too much, or simply different from the assumed amount?): *
(A) Ha: μ = 22
(B) Ha: μ > 21.2
(C) Ha: μ ≠ 22
(D) Ha: μ < 21.2
(E) Ha: μ < 22

26. Compute the appropriate test statistic.: *
(A) -1.8856
(B) -0.2667
(C) 0.2667
(D) 1.8856

: *

Choice (A)
Choice (B)
Choice (C)
Choice (D)
Choice (E)

Answer 1

Answer:

25. (E) Ha: < 22

26. (A) -1.8856

Explanation:

25.

We know that company claims that their fridges have an average of 22 gallons of useable space inside. Hence the customer being cheated if the usable space is too little.(i.e less than 22). Therefore the alternative hypothesis is correct in option E. Option A and C are wrong because these are two sided hypothesis but we need to test whether space is too little or not. In option B and D sample mean is given, but while setting hypothesis the population mean(claim) is used. So they are wrong.

(E) Ha: < 22 is correct

NOTE: null hypothesis is H0: = 22

26. Here one sample t-test is used

n= sample size = 50 ,  = sample mean = 21.2 , s= sample SD = 3

The formula for test statistics is

Hence option A is correct and other option as incorrect.