In: Statistics and Probability
a bait and tackle shop claims that the average trout caught in a nearby lake weighs 21 ounces with a standard deviation of 2.9 ounces. A random sample of 60 trout has a mean weight of 20.8 ounces. does the population differ significantly at the 0.05 level of significance?
Solution :
Given that,
Population mean = = 21
Sample mean = = 20.8
Population standard deviation = = 2.9
Sample size = n = 60
Level of significance = = 0.05
This is a two tailed test.
The null and alternative hypothesis is,
Ho: 21
Ha: 21
The test statistics,
Z = ( - )/ (/)
= ( 20.8 - 21 ) / ( 2.9 / 60)
= -0.53
P-value = 2*P(Z < z)
= 2*P(Z < -0.53)
= 2*0.2981
= 0.5962
The p-value is p = 0.5962 , and since p = 0.5962 ≥ 0.05, it is concluded that the null hypothesis is fail to reject.
Conclusion:
It is concluded that the null hypothesis Ho is fail to reject. Therefore, there is not enough evidence to claim that the population mean μ is different than 21, at the 0.05 significance level.