MA 203 DL Excel Project 4

Chapter 7

Fast Food Accuracy In a study of the accuracy of fast food drive-through orders, in QSR magazine, Mc Donald's had 33 incorrect orders out of the 362 orders observed. 1. Construct a 95% confidence interval for the proportion of the orders that are not accurate. Express the interval in a sentence that expresses the proportion as a percentage. The QSR study also showed that Burger King had 264 accurate and 54 inaccurate orders. 2. Construct a 99% confidence interval estimate of the percentage of inaccurate orders. The 99% CI for Wendy's in QSR magazine was 6.2% < p < 15.9%. 3. Construct the 99% confidence interval for McDonald's and then compare the three chains. 4. What do you conclude? Medication Usage In a survey of 3005 adults aged 57 through 85 years, it was found that 81.7% of them used at least one prescription medication. ("Use of Prescription and OTC Medications and Dietary Supplements Among Older Adults in the US," Qato, et al, JAMA Vol 300, No 24) 5A How many of the subjects used at least one medication? B Construct a 90% confidence interval estimate of the percentage of adults aged 57 through 85 years who use at least one medication. C What do the results tell us about the proportion of college students who use at least one prescription medication?

Arsenic in Rice Listed below are amounts of arsenic in micrograms per serving in samples of brown rice from California (based on FDA data; FDA and EPA guidelines generally say that anything under 10 is acceptable) 5.5 5.6 8.4 7.3 4.5 7.5 1.5 5.5 9.1 8.7 6A Construct a 90% confidence interval estimate of the mean. B The FDA also took samples in Arkansas... can we expect that interval estimate to be similar?

Mercury In Sushi The FDA guideline here is that the level of mercury should be below 1 ppm. The New York Times sponsored a study with the following results:

Store/Restaurant	Mercury Reading in Parts Per Million
D'Agostino	0.56
Eli's Manhattan	0.75
Fairway	0.10
Food Emporium	0.95
Gourmet Garage	1.25
Grace's Marketplace	0.54
Whole Foods	0.88

7A Construct a 98% confidence interval estimate of the mean. B Do you feel that this indicates that there is a safe amount or too much mercury in NYC Sushi tuna?

Insomnia Treatment A clinical trial was conducted to test the effectiveness of the drug zopiclone for treating insomnia in older patients.Before treatment, 16 subjects had a mean wake time of 102.8 minutes. After treatment with zopiclone, the 16 subjects had a mean wake time of 98.9 minutes with a standard deviation of 42.3 minutes. ("CBT vs Zopiclone for Treatment of Chronic Primary Insomnia in Older Adults," by Silverstein et al, JAMA, Vol 295, No 24) Assume that the values appear to be from a normally distributed population. 8 Construct a 98% confidence interval estimate of the mean. 9 Construct a 98% confidence interval estimate of the standard deviation 10 What do the results suggest about the mean wake time before the treatment? What do the results suggest about the effectiveness of zopiclone?

Highway Speeds Listed below are some speeds (in mph) measured from southbound traffic on I-280 near Cupertino, CA (according to Sig Alert). This is a simple random sample obtained on a weekday at 3:30 pm. 62 61 61 57 61 54 59 58 59 69 60 67 11 Use this sample data to construct a 95% confidence interval estimate of the population standard deviation. 12 Does the interval estimate describe the standard deviation for all times of the week? Why or why not?

As always, questions come from the 6^th Edition of Stats with Excel

n	25			Remember to update your chi-square values with each problem
s	0.24			And be aware of the tails:
Confidence	95				95		0.975	0.025
					90		0.95	0.05
Chi Sq L	12.401
ChiSq R	39.364
Variance Lower Bound	0.035118
Variance Upper Bound	0.111475
SD Lower Bound	0.187399
SD Upper Bound	0.333879