Statistics in excel | Statistics homework help
need solutions calculations but also excel solution
Q1.
For each of the following claims mention what type of test should be used (one-tail, two-tail) and set up the null and alternate hypothesis. Consider that the critical value is = CV (like for example 1.96). For each H0, mention the acceptance range. a) The 87Cents Store claims that their daily profit is at least $5000. b) The Pastry shop claims that its chocolate cookies have no more than 50% chocolate per cookie. c) PS193 claims that its students scored in the 95thile.
Q2. A researcher wishes to test the claim that the average cost of tuition and fees at a 4-year college at least $7000. She selects a random sample of 81 colleges and finds the mean to be $6900. The standard deviation is $500. a. Is there evidence to support the claim at α = .06? b. Suppose no claim was made but the researcher is thinking of making a claim using a 95% two-sided confidence interval. Using the same data, construct the CIE interval.
Q3. An educator claims that the average salary of substitute teachers in New York is at most $100 per day. A random sample of ten school districts is selected, and the daily salaries are shown. Is there evidence to support the claim at α = .05? 85 70 110 95 90 102 87 78 69 100 Note: you need to compute the average and stdev.
Q4 Short answer questions and multiple choice questions:
1. A confidence interval of 90% was used to estimate the proportion of customers who buy at least two items during their shopping mall experience. A random sample of 100 customers produced a confidence interval of: 49% +/- 4%. What is the best way to explain the result?
2. The range of values that the correlation coefficient can take is: a. –infinite to + infinite b. 0% to 100% c. -1 to 1 d. 0 to 100
3. A coefficient of correlation equal to -.78 shows: a strong correlation a weak correlation a moderate correlation r value is invalid
Q5. Consider the following excel regression analysis output. Explain the significance of the r, p, F value; Give the regression equation.
Q6. One of the stores is a proud sponsor of the college soccer team. They constantly try to raise money for the team and they want to determine if there is any type of relationship between the amount of contribution and the years that the alumnus has been out of school. Years (X) 1 5 3 10 6 6 2 Contribution (Y) 250 100 110 0 70 80 175
a. Using Excel construct a scatter plot. Discuss the output of the scatter plot.
b. Give (or calculate) the correlation coefficient.
c. Give (or calculate) the coefficient of determination.
d. Give (or calculate) the regression equation coefficients; Give the equation of regression.
e. (very important) Based on the above values, in detail draw the conclusion: Discuss the correlation coefficient r Discuss the coefficient of determination r2 Discuss in detail the meaning of the regression equation (x=0; y=0) f. How much would be the contribution of a student who graduated 7 years ago? After how many years after graduations the alumni will stop contributing.
