Coffee and doughnuts At a certain coffee shop, all the customers buy a cup of coffee; some also buy a dough-nut. The shop owner believes that the number of cups he sells each day is normally distributed with a mean of320 cups and a standard deviation of 20 cups. He alsobelieves that the number of doughnuts he sells each day is independent of the coffee sales and is normally distrib-uted with a mean of 150 doughnuts and a standard devia-tion of 12. a) The shop is open every day but Sunday. Assuming day-to-day sales are independent, what’s the probabil-ity he’ll sell over 2000 cups of coffee in a week? b) If he makes a profit of 50 cents on each cup of cof-fee and 40 cents on each doughnut, can he reasonably expect to have a day’s profit of over $300? Explain.c) What’s the probability that on any given day he’llsell a doughnut to more than half of his coffeecustomers?

A large corporation employs 19185 individuals. The average income of all employees is $70616, with a standard deviation of $19414 and is skewed to the right. Consider this to be the population distribution. You are given a data set consisting of the incomes of 120 randomly selected employees.

Insurance Company A claims that its customers pay less for car insurance, on average, than customers of its competitor, Company B. You wonder if this is true, so you decide to compare the average monthly costs of similar insurance policies from the two companies. For a random sample of 15 people who buy insurance from Company A, the mean cost is $154 per month with a standard deviation of $13. For 11 randomly selected customers of Company B, you find that they pay a mean of $159 per month with a standard deviation of $16. Assume that both populations are approximately normal and that the population variances are equal to test Company A’s claim at the 0.02 level of significance. Let customers of Company A be Population 1 and let customers of Company B be Population 2.   Step 2 of 3 :   Compute the value of the test statistic. Round your answer to three decimal places.

Insurance Company A claims that its customers pay less for car insurance, on average, than customers of its competitor, Company B. You wonder if this is true, so you decide to compare the average monthly costs of similar insurance policies from the two companies. For a random sample of 12people who buy insurance from Company A, the mean cost is $153 per month with a standard deviation of $16. For 15 randomly selected customers of Company B, you find that they pay a mean of $160 per month with a standard deviation of $10. Assume that both populations are approximately normal and that the population variances are equal to test Company A’s claim at the 0.10 level of significance. Let customers of Company A be Population 1 and let customers of Company B be Population 2. Step 1 of 3: State the null and alternative hypotheses for the test. Fill in the blank below. H0: μ1=μ2 Ha: μ1_____μ2 Step 2 of 3: Compute the value of the test statistic. Round your answer to three decimal places Step 3 of…

Insurance Company A claims that its customers pay less for car insurance, on average, than customers of its competitor, Company B. You wonder if this is true, so you decide to compare the average monthly costs of similar insurance policies from the two companies. For a random sample of 1313 people who buy insurance from Company A, the mean cost is $151$⁢151 per month with a standard deviation of $16$⁢16. For 99 randomly selected customers of Company B, you find that they pay a mean of $158$⁢158 per month with a standard deviation of $19$⁢19. Assume that both populations are approximately normal and that the population variances are equal to test Company A’s claim at the 0.050.05 level of significance. Let customers of Company A be Population 1 and let customers of Company B be Population 2. Step 2 of 3:  Compute the value of the test statistic. Round your answer to three decimal places.

MC Qu. 10-64 Sales at a fast-food restaurant average... Sales at a fast-food restaurant average $6,000 per day. The restaurant decided to introduce an advertising campaign to Increase daily sales. In order to determine the effectiveness of the advertising campaign, a sample of 49 day's sales were taken. The sample showed average daily sales of $6,300. From past history, the restaurant knew that its population standard deviation is about $1,000. If the level of significance is 0.01, have sales increased as a result of the advertising campaign? Multiple Choice Fail to reject the null hypothesis. Reject the null hypothesis and conclude the mean is higher than $6,000 per day. Reject the null hypothesis and conclude the mean is lower than $6,000 per day. Reject the null hypothesis and conclude that mean equal to $6,000 per day.

Records from the Washington Department of Licensing show that 47 former SFCC business students have incorporated their own businesses in the last five years.  Eight of these students are selected at random and contacted.  Each is asked how many people are employed by their corporation.  The responses are: 7, 12, 13, 17, 10, 5, 10, and 6 employees. What is your best estimate of the standard deviation of the  number of employees for all 47 corporations?

The salaries of professional baseball players are heavily skewed right with a mean of $3.2 million and a standard deviation of $2 million. The salaries of professional football players are also heavily skewed right with a mean of $1.9 million and a standard deviation of $1.5 million. A random sample of 40 baseball players’ salaries and 35 football players’ salaries is selected. The mean salary is determined for both samples. Let  represent the difference in the mean salaries for baseball and football players. Which of the following represents the shape of the sampling distribution for ? skewed right since the populations are both right skewed skewed right since the differences in salaries cannot be negative approximately Normal since both sample sizes are greater than 30 approximately Normal since the sum of the sample sizes is greater than 30