Mike D. answered 06/01/21
Effective, patient, empathic, math and science tutor
HO : population mean = 268
H1 : population mean > 268
population standard deviation unknown but sample size is large > 30, so use z test
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test statistic = ( 277 - 268) / 40 / √45 = 1.51
Right tailed test as H1 has >
critical value of Z when alpha = 0.05 is 1.64
as 1.51 < 1.64 we have insufficient evidence to reject H0 (and accept H1) so insufficient evidence to support the claim made.