Question

4 of 13 < > -14 View Policies Current Attempt in Progress A random sample of 119 observations produced a sample mean of 30. Find the critical and observed values of z for the following test of hypothesis using a = 0.02. The population standard deviation is known to be 7 and the population distribution is normal. Ho: u = 28 versus H : 1 # 28. Round your answers to two decimal places. Zcritical left = i i Zcritical right Zobserved i

Answer 1

Solution:

We are given

α = 0.02

Test is two tailed test.

So, critical Z values by using z-table are given as below:

Z_{critical left} = -2.33

Z_{critical right} = 2.33

The test statistic formula is given as below:

Z_observed = (x̄ - µ)/[σ/sqrt(n)]

From given data, we have

µ = 28

x̄ = 30

σ = 7

n = 119

Z_observed = (30 - 28)/[7/sqrt(119)]

Z_observed = 3.12

Z_observed = 3.12