a)
H0: μ1 = μ2
z = (xbar1-xbar2) / sqrt( σ1^2 /n1 +σ2^2/n2)
sqrt( σ1^2 /n1 +σ2^2/n2) = sqrt ( 4.5^2/30 + 4^2/30) = 1.099242
z = (67.5 - 64.6) = 2.9 / 1.099242
z =2.6382
b)
Find the p-value
P( z > 2.6382) = 0.0041
Since the p-value is smaller than the significance level of 0.05, we reject the null hypothesis; there is sufficient evidence to conclude that the average retirement age at ShopRite is higher than it is in Boscov’s.
Can someone please help how to solve this I keep getting the wrong answer so I am now freaking out and clueless
23) The following data show the average retirement ages for a random sample of workers in Boscov’s and a random sample of workers in ShopRite.
Boscov’s: Sample mean is 64.6 years, sample size is 30, population standard deviation is 4 years
ShopRite: Sample mean is 67.5 years, sample size is 30, population standard deviation is 4.5 years
a) Perform a hypothesis test using alpha = .05 to determine if the average retirement age at ShopRite is higher than it is in Boscov’s.
b) Determine the p value and interpret the results.
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