Hypothesis testing of means sigma known

[jolie]

Hello to all

Can someone please check to see if I have the correct answer? Thanks

Various temperature measurements are recorded at different times for a particular city. The mean of 25C is obtained for 60 temperatures on 60 different days. Assuming that pop st/deviation is 1.5C, test the claim that the population mean is 23C. Use a 0.05 significance level.

I am using TI 84

Z.Test/Stats
Mu:23
St/Dev: 1.5
-X: 25
n:60
Tot:=/ Mu
Reject Ho if
P < 0.05
5.38< 0.05
Yes

1)Ho:Mu=23
2)Ha:Mu=/ 23
3)P: 5.38....
4)obs:10.3
5)Reject ho
6)Sample evidence support claim that the population mean is 23C

[jamesmartinn]

Zobs = X - u / pop.std
= 25 - 23 / 1.5
= 1.33

With alpha = 0.05, the two-tail Z critical = +/- 1.96

Zobs (+1.33) < Zcritical (+1.96); Fail to Reject your Null Hypothesis.