Customers at Costco spend an average of $130 per trip (The Wall Street Journal, October 6, 2010). One of Costco’s rivals would like to deter

Question

Customers at Costco spend an average of $130 per trip (The Wall Street Journal, October 6, 2010). One of Costco’s rivals would like to determine whether its customers spend more per trip. A survey of the receipts of 25 customers found that the sample mean was $135.25. Assume that the population standard deviation is $10.50 and that spending follows a normal distribution. Use standard normal curve area table.A, Specify the appropriate null and alternative hypotheses to test whether average spending at the rival�s store is more than $130.B. Calculate the value of the test statistic.C. Calculate the p-value.D. Calculate the critical value

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Thiên Di 5 years 2021-09-05T04:00:53+00:00 1 Answers 19 views 0

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  1. nguyetanh
    0
    2021-09-05T04:02:32+00:00
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    Answer:

    Step-by-step explanation:

    Given the following :

    Average amount spent (U) = $130 per trip

    Sample size (n) = 25

    Sample mean (m) = $135.25

    Population standard deviation (sd) = $10.50

    Assume a standard distribution.

    A.) Null hypothesis ; Alternative hypothesis

    Hnull : U ≤ 130 ; Ha : U > 130

    B.) value of test statistic :

    Z = (m – U) / standard error

    Standard Error = sd / sqrt(n)

    Standard Error( S.E)= 10.50 / sqrt(25)

    S.E = 10.50 / 5 = 2.1

    Hence,

    Z = (135.25 – 130) / 2.1

    Z = 5.25 / 2.1

    Z = 2.5

    C. Calculate the p-value.

    Using the p value calculator by entering the z-score above, the p value obtained is 0.0124

    P value = 0.01

    D. Calculate the critical value

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