Question

A market research firm studied the waiting time to order drinks during breakfast time at drive-thru in two coffee shop chains. For a sample of 30 locations of chain A, the sample standard deviation of waiting time was 21.2 seconds, and for a sample of 28 locations of chain B, the sample standard deviation was 31.4 seconds. Do these data suggest that the waiting time is more consistent in chain A

Answer 1

Answer:

Yes

Step-by-step explanation:

Given that :

CHAIN A:

Sample size n1 = 30

Sample standard deviation of waiting time s1 = 21.2

CHAIN B:

Sample size, n2 = 28

Sample standard deviation of waiting time s2 = 31.4

Null hypothesis H0: s1 = s2

Alternative hypothesis H1: s1 < s2

Test statistic ; Ftest : s1² / s2²

Ftest = 21.2^2 / 31.4^2

= 0.4558399

P value from F statistic : = 0.02 (using p value calculator)

Since the pval < 0.05

Then we reject the Null ; Chain A waiting time is more consistent