Population 1 has mean
µ1 and variance o12 and population 2 has mean
µ2 and variance o22. A sample of size
n1 is drawn from population 1 and a sample of size n2 is drawn from population 2. If n1 and n2 are >= 30, which of the following statements is not necessarily true of the sampling distribution of the difference between the sample means?
A sample of 30 men watch an average of 30 hours television a week with a standard deviation of 4 hours whereas a sample of 40 women watch an average of 25 hours a week with a standard deviation of 2 hours. Calculate an approximate 95% confidence interval for the difference between the two population means?
Suppose we wish to test whether men watch more television than women using the sample information in question 2.What are the null and alternative hypotheses of the test?
Carry out the test of whether men watch more television than women using the sample information in question 2. What is the p-value?
For the test carried out in question 4, what conclusion do you reach?
If sample 1 is of size 10 and has standard deviation 4 and sample 2 is of size 8 and has standard deviation 2, calculate a pooled estimate of the common variance assuming that both populations are normal and both populations have a common variance.
You wish to test (at the 5% level) the difference between two means using the means and standard deviations from two small samples, size 10 and 12 respectively assuming that the population variances are the same. You obtain a t value of 2.528. What do you conclude?
Which of the following samples are not paired?
To compare two population means when the two samples paired, we should
Which of the following statements is true?
