Statistics and Probability Answers

If P.A/ D 0:4 and P.B/ D 0:6, then A and B must be mutually exclusive.

If A and B are any two events of a sample space S, then P.A/ D P.A and B/ 􀀀 P.B/.

f A and B are any two events of a sample space S, then P.A/ D P.A and B/ 􀀀 P.B/.

If A and B are independent events with P.A/ D 0:35 and P.B/ D 0:55, then P.AjB/ is 0:35=0:55 D

0:64:

An approach of assigning probabilities which assumes that all outcomes of the experiment are

equally likely is referred to as the relative frequency approach.

A journalist would like to report on the traffic–related tardiness incurred by employees

in a certain city per year. To do this, he asked 25 employees and found out that they were

late for an average of 8.5 times a year due to traffic. The sample standard deviation was found to be in 1.5 times.

1. At a confidence level of 90 percent, determine the confidence interval that will

estimate the population mean.

2. At a confidence level of 95 percent, determine the confidence interval that will

estimate the average number of traffic-related tardiness per year by employees in

a city.

3. Which between the answers to items a and b gave a wider margin of error? What

does this say about the relationship between the confidence level and the margin

of error?

Find the mean and variance of normal distribution using density function

If Y1, Y2 are identically independently distributed as normal distribution with mean u

In order for a candy company to claim that a bridge mix is mostly chocolate stars, a proportion of at least 0.8 of the packages must contain 3 ounces or more of chocolate stars. Quality control tests a random sample of 50 packages to determine if the proportion is less than 0.8 at a significance level of 0.05. Use Sheet 4 of the Excel file to calculate p^

, the z

-score, and the p

-value