Question 1. The data for question 1 is contained in the file, Course_Scores.xls. This problem concerns course scores (on a scale from 0-100) for a large undergraduate computer-programming course. The class is composed of both underclassmen (freshmen and sophomores) and upperclassmen (juniors and seniors). Also, the students are categorized according to their previous mathematical background from previous courses as 'low' or 'high' mathematical background. The variables in the excel file are:

- Score: On a scale from 0 - 100
- UpperCI: 1 for upperclassmen, 0 for underclassmen
- HighMath: 1 for high mathematical background, 0 otherwise

For the questions below, assume the data in file Course_Scores.xls represent a random sample for all college students. Answer the following questions:

a. Find the mean score and 95% confidence interval for all students
b. Find the mean score and 95% confidence interval for all upperclassmen
c. Find the mean score and 95% confidence interval for all upperclassmen with high math background
d. The professor of this course believes he has enough evidence to prove the hypothesis that upperclassmen score at least 5 points better, on average, than underclassmen. Do you agree with this statement? Conduct a test at the ± = .05 level of significance.
e. If we consider a good grade to be a score of 80 or above, is there enough evidence to reject the null hypothesis that the fraction of good grades is the same from low math backgrounds as those with high math backgrounds? Conduct a test at the ± = .05 level of significance.
f. Perform a similar test as in part e, but instead of math background, compare upperclassmen to underclassmen

Assume that in a hypothesistest with null hypothesis H 0: mu = 14.0 at alpha = 0.05, that a value of 13.0 for the sample mean results in the null hypothesis being rejected. That corresponds to a confidenceinterval result of:
a) the 95% confidenceinterval for the mean contains the value 14.0
b) the 95% confidenceinterval

Assume that in a hypothesistest with null hypothesis = 13.0 at 0.05, that a value of 11.0 for the sample mean results in the null hypothesis not being rejected. That corresponds to a confidenceinterval result of
A. The 95% confidenceinterval for the mean does not contain the value 13.0
B. The 95% confidenceinterval for

1. What are the null and alternate hypotheses for this test? Why?
2. What is the critical value for this hypothesistest using a 5% significance level?
3. Calculate the test statistic and the p-value using a 5% significance level.
4. State the decision for this test.
5. Determine the confidenceinterval level that would be a

A confidenceinterval for the population mean tells us which values of mean are plausible (those inside the interval) and which values are not plausible (those outside the interval) at the chosen level of confidence. You can use this idea to carry out a test of any null hypothesis. Ho:mean =Mo starting with a confidence interva

Compute a 95% confidenceinterval for the population mean, based on the sample 1.5, 1.54, 1.55, 0.09, 0.08, 1.55, 0.07, 0.99, 0.98, 1.12, 1.13, 1.00, 1.56, and 1.53. Change the last number from 1.53 to 50 and recalculate to the confidenceinterval. Using the results, describe the effect of an outlier or extreme value on the conf

Consider the following HypothesisTesting:
H0: δ1² = δ2²
Ha: δ1² ≠ δ2²
The sample size for sample 1 is 25, and for sample 2 are 21. The variance for sample 1 is 4.0 and for sample 2 is 8.2
a) at the confidence level of 0.98, what is your conclusion of this test?
b) What is the confidence

Jacob Lee is a frequent traveler between Los Angeles and San Francisco. For the past month, he wrote down the flight times on three different airlines. The results are found in the attachment.
a. Use the .05 significance level and the five-step hypothesis-testing process to check if there is a difference in the mean flight ti

What is the relationship between a confidenceintervaland a single sample, two-tailed hypothesistest?
How are they the same? How are they different?
Review the definition of a single sample, two tailed test. Now review the structure of a confidenceinterval.
What are the assumptions and requirements for the use

A. *HT* A test was conducted to compare the wearing quality of the tires produced by two tire companies. A random sample of 16 cars is equipped with one tire of Brand X and one tire of Brand Y (the other two tires on each car are not part of the test), and driven for 30 days. The following table gives the amount of wear in thous