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# Confidence interval, Null Hypothesis

1) A random sample of size 15 taken from a normally distributed population revealed a sample mean of 75 and a sample variance of 25. The upper limit of a 95% confidence interval for the population mean would equal?

2. Based on sample data the 90% confidence interval limits forth population mean are 170.86 and 195.42. If the 10% level of significance was used in testing the hypthesis H1o:u=201, H1" u = 201 the null hypothesis:

would be rejected
would not be rejected
would have to be revealed
none of the above

#### Solution Preview

1) a random sample of size 15 taken from a normally distributed population revealed a sample mean of 75 and a sample variance of 25. The upper limit of a 95% confidence interval for the population mean would equal?

Sample standard deviation=square root of Variance=square root of 225= 15

95% Confidence limits

Mean=M = 75
Standard deviation =s= 15
sample size=n= 15 ...

#### Solution Summary

Answers questions on confidence interval, null hypothesis.

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