Executives of a supermarket chain are interested in the amount of time that customers spend in the stores during shopping trips. The executives hire astatistical consultant and ask her to determine the mean shopping time, µ, of customers at the supermarkets. The consultant will collect a random sample ofshopping times at the supermarkets and use the mean of these shopping times to estimate u. Assuming that the standard deviation of the population ofshopping times at the supermarkets is 28 minutes, what is the minimum sample size she must collect in order for her to be 90% confident that her estimate iswithin 3 minutes of u?Carry your intermediate computations to at least three decimal places. Write your answer as a whole number (and make sure that it is the minimum wholenumber that satisfies the requirements).(If necessary, consult a list of formulas.)

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A First Course in Probability (10th Edition)

10th Edition

ISBN:9780134753119

Author:Sheldon Ross

Publisher:Sheldon Ross

Chapter1: Combinatorial Analysis

Section: Chapter Questions

Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...

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The speed of cars driving past Johnson City High School, on 666 Reynolds Rd, were recorded over one school year. The speed limit on that part of Reynolds Rd is 20 mph. The mean of the speed readings was 24.19 mph, with a standard deviation of 3.56 mph.
can you fill in the blanks
A boat capsized and sank in a lake. Based on assumption of mean weight of 131 lb, the boat was rated to carry 70 passengers (so the load limit was 9,170 lb). After the boat sank, the assumed mean weight for similar boats was changed from 131 lb to 173 lb. Complete parts a and b below A. Assume that a similar boat is loaded with 70 passengers, and assume that the weight of people are normally distributed with a mean of 180.7 lb and a standard deviation of 39.2 lb. Find the probability that the boat is overloaded because the 70 passengers have a mean weight greater than 131 lb
A physical therapist wanted to know whether the mean step pulse of men was less than the mean step pulse of women. She randomly selected 54 men and 70 women to participate in the study. Each subject was required to step up and down a 6-inch platform. The pulse of each subject was then recorded. The following results were obtained. Two sample T for Men vs Women N Mean StDev SE Mean Men Women 98% CI for mu Men - mu Women (- 12.20, - 1.00) T-Test mu Men = mu Women (vs H2 O C. Ho: H1 = H2; Ha: H1 #H2 (b) Identify the P-value and state the researcher's conclusion if the level of significance was a = 0.01. What is the P-value? P-value =
Assume that you have been provided the following information for a sample of cars The covariance between weight and miles per gallon is equal to -4.9 pound-miles. The standard deviation of the cars' mileages is 7.75. The standard deviation of the cars' weights is 0.94. Estimate the correlation coefficient to the first decimal place.
The chocolate chip cookies that are produced at Perry’s Cookie Emporium have weights which are approximately normally distributed with the mean weight 180 grams and with standard deviations 20 grams. The cookies, however, are sold by count, not by weight. Perry wants to improve his image, so he decides to set aside lightest 20% of the cookies to be packaged and sold separately. What cookie weight will divide the lightest 20% from the heaviest 80%?
Ensure the RaceResults worksheet is active, then use the FREQUENCY function to calculate the frequency distribution of the race results in column D. Place your results in the range G4:G9. Enter a function in cell F22 to calculate the correlation between age (Columns C) and race time (Column D). Enter a function in cell G22 to calculate the covariance between age and race time. Enter a function in cell H22 to calculate the variance of the ages in the data set. Note this is a sample of data not a population. Enter a function in cell 122 to calculate the standard deviation of the ages in the data set.
A random sample of five observations from three normally distributed populations produced the following data: (You may find it useful to reference the F table.) (table is the screenshot picture) a. Calculate the grand mean. (Round intermediate calculations to at least 4 decimal places and final answer to 4 decimal places.) b. Calculate SSTR and MSTR. (Round intermediate calculations to at least 4 decimal places and final answers to 4 decimal places.) c. Calculate SSE and MSE. (Round intermediate calculations to at least 4 decimal places and final answers to 4 decimal places.) d. Specify the competing hypotheses in order to determine whether some differences exist between the population means. _H0: μA = μB = μC; HA: Not all population means are equal. _H0: μA ≤ μB ≤ μC; HA: Not all population means are equal. _H0: μA ≥ μB ≥ μC; HA: Not all population means are equal. e-1. Calculate the value of the F(df1, df2) test statistic. (Round intermediate calculations to at least 4 decimal…
The distribution of the student heights at a large college is approximately bell shaped. If the mean height is 66 inches,and approximately 95% of the heights fall between 32 and 100 inches, then, the standard deviation of the heightdistribution is approximately equal to
A report stated that after obtaining a bachelor's degree, 43% of college students enroll in a graduate degree program. For a random sample of 61 undergraduate students, find the mean, variance and standard deviation for the number of students who will enroll in a graduate degree program after obtaining a bachelor's degree. a.) mean b.) variance c.) standard deviation (round to two decimal places)
Justin wants to know whether a commonly prescribed drug does improve the attention span of students with attention deficit disorder (ADD). He knows that the mean attention span for students with ADD who are not taking the drug is 2.3 minutes long. His sample of 12 students taking the drug yielded a mean of 4.6 minutes. Justin can find no information regarding σx , so he calculated s2x =1.96. a. Identify the independent and dependent variables. b. In a sentence, state the null hypothesis being tested. c. Using symbols, state the null and alternative hypotheses. d. Determine the critical region using a one-tailed test with alpha = .05. e .Conduct the hypothesis test (Do the math and compare the t-critical and t-obtained values). f. State your conclusions in terms of H0 (Should you reject the H0 or fail to reject/accept the H0). g. Based on your analysis, is there a relationship between the drug and attention span?
Actuaries use various parameters when evaluating the cost of a life insurance policy. The variance of the life spans of a population is one of the parameters used for the evaluation. Each year, the actuaries at a particular insurance company randomly sample 30 people who died during the year (with the samples chosen independently from year to year) to see whether the variance of life spans has changed. The life span data from this year and from last year are summarized below. Current Last Year Year *1 = 75.8 x2 = 76.2 s3 = 47.61 s3= 92.16 (The first row gives the sample means and the second row gives the sample variances.) Assume that life spans are approximately normally distributed for each of the populations of people who died this year and people who died last year. Can we conclude, at the 0.05 significance level, that the variance of the life span for the current year, of, differs from the variance of the life span for last year, o,? Perform a two-tailed test. Then complete the…

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