Answer:
The value of z test statistics for the appropriate hypothesis test is 1.90.
Step-by-step explanation:
We are given that the response times of technicians of a large heating company follow a Normal distribution with a standard deviation of 10 minutes.
He takes a random sample of 25 response times and calculates the sample mean response time to be 33.8 minutes.
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<u><em>Let </em></u><u><em> = mean response time.</em></u>
So, Null Hypothesis, : = 30 minutes {means that the mean response time is 30 minutes}
Alternate Hypothesis, : > 30 minutes {means that the mean response time has increased from the target of 30 minutes}
The test statistics that would be used here <u>One-sample z test statistics</u> as we know about the population standard deviation;
T.S. = ~ N(0,1)
where, = sample mean response time = 33.8 minutes
= population standard deviation = 10 minutes
n = sample of response times = 25
So, <u><em>test statistics</em></u> =
= 1.90
Hence, the value of z test statistics for the appropriate hypothesis test is 1.90.