interval for the population mean based on the following sample Sample 4 6 6 7 8

Interval for the population mean based on the

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interval for the population mean, based on the following sample Sample 4, 6, 6, 7, 8, 9, 9, 12, 15 Average Standard deviation Sample size Degrees of Freedom Confidence Interval 95% Interval lower limit 95% Interval upper limit Question 4: A company produces light bulbs and advertises that their light bulbs last t α /2
2,000 hours. Use the data below to conduct a 95% confidence on the light bulb hrs. Sample of light bulbs shows the following bulb life 1702, 1832, 1909, 1955, 1987, 2012, 2332, 2422, 2439, 2453, 2566, 2643, 2677, 2701 Average Standard deviation Sample size Degrees of Freedom 95% Interval lower critical level 95% Interval upper critical level Based on your results, can you safely state that the company advertising is fair? Question 5: The marketing manager has stated that she believes that weekly product sales are limited at some of the stores based on the amount of shelf space provided. She takes a random sample of 12 stores to determine if shelf space is related to weekly sales. She gets the following results from her linear regression y= 7.4x + 145 y is shelf space x is sales a. How much variance in weekly sales does shelf space explain? b. What is the coefficient of correlation (r)? c. How would you rate this relationship (strong positive, weak negative, etc.) d. Should you feel comfortable using this to predict sales using shelf space? e. How much would you expect sales to be at a store with 12 feet of shelf space? t α/2 R 2 = .6839
1000 2600 0.98 11500 14100 980 -1250 12850 132000 137000 -77000 -82000 55000 -39000 -3000 5 49 245 13000 7 57 399 12 644 10 53 530 2 51 102 632 15000 17000 42000 32000 16000 2.625
275000 60000 32000 0.05 90000 26000 13750 150000 58000 -7550 100000 2900 3000 6200 400000 28000 -3450 24550

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