A tele-marketing company wants to know if sales go up as they call more people per day but spend less time per call. The following is the data from nine randomly selected days. The information is the number of calls the salesperson makes in a day and the total amount of sales (in thousands of dollars).

Calls             25      29      33      37      43      48      52      55      67

Sales            3.7     4.2     4.2     5.0     4.7     5.3     4.9     5.6     5.9

a. Calculate ∑X, ∑X², ∑Y, ∑Y², ∑XY

b. Calculate SS_XX, SS_YY, and SS_XY.

c. Use the information from parts (a) and (b) to generate the estimated OLS line.

d. Interpret the estimated slope coefficient from your line in part c.

e. Predict the amount of sales for the fourth observation in the data set.

f. Calculate the residual for that observation.

g. Construct the ANOVA table for this situation.

h. Calculate the coefficient of determination.

i. Interpret the coefficient of determination.

j. Using alpha = 0.05, use a model test to see if a linear relationship exists between the number of calls and sales.

k. A positive relationship is anticipated between these two variables. At alpha = 0.05, test to see if the evidence supports that anticipated sign.

l. Construct a 98% confidence interval for the population slope coefficient.

The College Board provided comparisons of Scholastic Aptitude Test (SAT) scores based on the highest level of education attained by the test taker's parents. A research hypothesis was that students whose parents had attained a higher level of education would on average score higher on the SAT. The overall mean SAT math score was 514. SAT math scores for independent samples of students follow. The first sample shows the SAT math test scores for students whose parents are college graduates with a bachelor's degree. The second sample shows the SAT math test scores for students whose parents are high school graduates but do not have a college degree.
College Grads
501   487
534   533
666   510
554   394
566   531
556   594
481   464
608   485

High School Grads
442   492
580   478
479   425
486   485
528   390
524   535
(a)
Formulate the hypotheses that can be used to determine whether the sample data support the hypothesis that students show a higher population mean math score on the SAT if their parents attained a higher level of education. (Let μ1 = population mean verbal score of students whose parents are college graduates with a bachelor's degree and μ2 = population mean verbal score of students whose parents are high school graduates but do not have a college degree.)

H0: μ1 − μ2 = 0
Ha: μ1 − μ2 ≠ 0

H0: μ1 − μ2 < 0
Ha: μ1 − μ2 = 0
  

H0: μ1 − μ2 ≠ 0
Ha: μ1 − μ2 = 0

H0: μ1 − μ2 ≥ 0
Ha: μ1 − μ2 < 0

H0: μ1 − μ2 ≤ 0
Ha: μ1 − μ2 > 0
(b)
What is the point estimate of the difference between the means for the two populations?

(c)
Find the value of the test statistic. (Round your answer to three decimal places.)

Compute the p-value for the hypothesis test. (Round your answer to four decimal places.)
p-value =
(d)
At
α = 0.05,
what is your conclusion?
Do not Reject H0. There is sufficient evidence to conclude that higher population mean verbal scores are associated with students whose parents are college graduates.
Reject H0. There is sufficient evidence to conclude that higher population mean verbal scores are associated with students whose parents are college graduates.
Reject H0. There is insufficient evidence to conclude that higher population mean verbal scores are associated with students whose parents are college graduates.
Do not reject H0. There is insufficient evidence to conclude that higher population mean verbal scores are associated with students whose parents are college graduates.

Smudge pots are sometimes used to protect orchards from frost. Two types of smudge pots are to be compared to determine which has the longest average burn time. Ten pots of each type are randomly selected for the study. These twenty pots will be lit and the burn time for each recorded. What is the appropriate type of analysis?

a. One sample t test of significance on μ .

b. Matched pairs t test of significance on μ . d

c. Two independent sample t test on μ . 1 − μ2 d. One sample z test on proportion, p

. e. Two sample z test on p1 − p2

Professional basketball has truly become a sport that generates interest among fans around the world. More and more players come from outside the United States to play in the National Basketball Association (NBA). You want to develop a regression model to predict the number of wins achieved by each NBA team, based on field goal (shots made) percentage and three-point field goal percentage. The data are stored in NBA.xlsx

1) At the 0.05 level of significance, perform a F test to determine whether the regression model has any significant variable. Use p-value to explain.

How can I do one-way ANOVA in RStudio?

1. Scores on an MBA placement exam are reported to have a normal distribution with standard deviation 18. The exam officials stated that the average score for all students was 70. You take a random sample of 50 students and find their average score is 67. Use your data to estimate the mean score for all students taking the MBA placement exam -Verify your answer using calculations and show your work.

2. Students at the union want to estimate the average number of ounces of coffee in a cup. They take a random sample of 40 cups and find the mean is 5.2 ounces. Assume amount dispensed has a normal distribution and that the standard deviation is set at 0.24 ounces per cup. Find your best estimate for the average amount of coffee being dispensed by this machine. Verify your answer using calculations and show your work.

When testing gas pumps for​ accuracy, fuel-quality enforcement specialists tested pumps and found that 1345 of them were not pumping accurately​ (within 3.3 oz when 5 gal is​ pumped), and 5637 pumps were accurate. Use a 0.01 significance level to test the claim of an industry representative that less than​ 20% of the pumps are inaccurate. Use the​ P-value method and use the normal distribution as an approximation to the binomial distribution.

z=

t=

please expalin steps to take and also if you know the steps on ti-84 calculator please

The proportion of public accountants who have changed companies within the last three years is to be estimated within 4%. The 95% level of confidence is to be used. A study conducted several years ago revealed that the percent of public accountants changing companies within three years was 22. (Use z Distribution Table.) (Round the z-values to 2 decimal places. Round up your answers to the next whole number.)

a. To update this study, the files of how many public accountants should be studied?

b. How many public accountants should be contacted if no previous estimates of the population proportion are available?

I want to find out what the undergraduate student body thinks about the move to Division I sports, which will involve higher student fees to support the athletic program. Every evening I go to Library Walk and I ask everyone who passes by whether or not they support the move to Division I, and get 1050 responses. From this data, I calculate the proportion that support moving to Division I. I find that only 25% of those surveyed support the move to D1.

1. Can I construct a 95% confidence interval for the overall level of support for this change to D1 sports? Why or why not?

A manufacturer claims that the calling range (in feet) of its 900-MHz cordless telephone is greater than that of its leading competitor. A sample of 1919 phones from the manufacturer had a mean range of 12301230 feet with a standard deviation of 3131 feet. A sample of 1111 similar phones from its competitor had a mean range of 11901190 feet with a standard deviation of 4242 feet. Do the results support the manufacturer's claim? Let μ1μ1 be the true mean range of the manufacturer's cordless telephone and μ2μ2 be the true mean range of the competitor's cordless telephone. Use a significance level of α=0.1α=0.1 for the test. Assume that the population variances are equal and that the two populations are normally distributed.

Step 2 of 4 :  

Compute the value of the t test statistic. Round your answer to three decimal places.

step 3 t/|t| is </> ____

reject, fail to reject

According to a survey by TD Ameritrade, one out of four investors has exchange-traded funds in their portfolios (USA Today, January 11, 2007). Consider a sample of 40 investors.

Compute the probability of exactly 7 investors having exchange-traded funds in their portfolio.

Compute the probability that at least 5 of the investors have exchange-traded funds in their portfolio.

Compute the probability that at most 4 of the investors have exchange-traded funds in their portfolio.

Find the mean and standard deviation.

If you found that exactly 10 of the investors have exchange-traded funds in the

portfolio would you doubt the accuracy of the survey and why?

This semester we have discussed the following statistical analyses.             

Z-test               One-Sample t-test                   Independent Groups t-test                  Repeated Measures t-test

One-Way ANOVA                             Regression                                           Correlation

1. Research shows that people who do well on the SAT tend to do well in college (they have a higher GPA). Likewise, students who do not do well on the SAT struggle in college (they have a lower GPA). This information is used by college admissions officials to determine if a student should be admitted or not.                                                                                                                                                                            5 points

Which of the statistical analyses described above was used to make a determination about your success as a student at WSU? Be specific.

2. Researchers are interested in the relationship between height and academic achievement. To do so, they want to investigate the relationship between GPA and height in inches.

Which of the tests indicated above should be used and why?

Which one is Correlation and which one is Regression? Why?

2. The weights of American newborn babies are normally distributed with a mean of 119.54 oz (about 7 pounds 8 ounces) and a population standard deviation of 0.67 oz. A sample of 14 newborn babies is randomly selected from the population.

(a) Find the standard error of the sampling distribution. Round your answer to 4 decimal places.

(b) Using your answer to part (a), what is the probability that in a random sample of 14 newborn babies, the mean weight is at most 119.09 oz? Round your answer to 4 decimal places.

(c) Using your answer to part (a), what is the probability that in a random sample of 14 newborn babies, the mean weight is more than 120.03 oz? Round your answer to 4 decimal places.

What is the meaning of the term "multicollinearity? Why is it important in assessing the strength of a multiple regression model?

Suppose that 72% of all adults think that the overall safety of airline travel is either good or excellent. An opinion poll plans to ask an SRS of 1097 adults about airplane safety. The proportion of the sample who think that the overall safety of airline travel is either good or excellent will vary if we take many samples from this same population. The sampling distribution of the sample proportion is approximately Normal with mean 0.72 and standard deviation about 0.012. Sketch this Normal curve and use it to answer the following questions. (Round your answers to three decimal places.)

(a)What is the probability that the poll gets a sample in which more than 74.4% of the people think that the overall safety of airline travel is either good or excellent?

(b)What is the probability of getting a sample that misses the truth (72%) by 2.4% or more?