1. In a statistical test of hypotheses, we reject the null hypothesis at alpha if:
a) The p-value is smaller than alpha.
b) The sample statistic is larger than alpha.
c) The p-value is larger than alpha.
d) The sample statistic is smaller than alpha.
e) None of the abone
2. Forty five CEO's from the electronics industry were randomly sampled and 95% confidence interval for the average salary of all Electronics CEO's was constructed. The interval was ($994,667 , 1,797,100) To make more useful inferences from the data, it is desired to reduce the width of confidence interval. Which of the following will result in a reduced interval width?
a) Increase the sample size, and increase the confidence level.
b) Decrease the sample size, and increase the confidence level.
c) Increase the sample size, and decrease the confidence level
d) The confidence interval cannot be changed. It is fixed
3. What happens to the distribution of a sample mean if we increase the sample size from 50 t0 60?
a) The mean would remain the same and the standard deviation would increase
b) The mean and the standard deviation would both decrease
c) The nean and the standard deviation would both remain the same
d) The mean would increase and the standard deviation would decrease
e) The mean would remain the same and the standaed deviation would decrease.
4. Which of the following graphical methods cannot be used on a categorical data set?
a) a bar cart
b) A stem-and-leaf display
c) A pie chart
d) All of these methods can be used