A weight-loss company wants to statistically prove that its methods work. They randomly selected 10 clients who had been on the weight loss program for between 55 and 65 days. They looked at their beginning weights and their current weight. The statistical test they should utilize is: t test for difference in paired samples z test for two population means z test for two population proportions t test for two population means 2. The mean of a normal distribution is 400 pounds. The standard deviation is 10 pounds. What is the probability of a weight between 415 pounds and the mean of 400 pounds? 0.3413 0.4332 0.5000 0.1932 3. The distribution of a sample of the outside diameters of PVC pipes approximates a symmetrical, bell-shaped distribution. The arithmetic mean is 14.0 inches, and the standard deviation is 0.1 inches. About 68% of the outside diameters lie between what two amounts? 13.0 and 15.0 inches 13.5 and 14.5 inches 13.9 and 14.1 inches 13.8 and 14.2 inches 4. A time series trend equation for Hammer Hardware is Y' = 5.6 + 1.2t, where sales are in millions of dollars and t increases by one unit for each year. If the value of sales in the base year of 2016 is $5.6 million, what would be the estimated sales amount for 2018? $6.8 million $5.6 million $8 million Unable to determine from given information 5. The tread life of tires mounted on light-duty trucks follows the normal probability distribution with a mean of 60,000 miles and a standard deviation of 4,000 miles. Suppose you bought a set of four tires, what is the likelihood the mean tire life of these four tires is between 57,000 and 63,000 miles? Very likely 1.00 0.4332 0.8664 6. What is the median of 26, 30, 24, 32, 32, 31, 27, and 29? 30 32 29 29.5 7. As the size of the sample increases, what happens to the shape of the distribution of sample means? It cannot be predicted in advance. It approaches a normal distribution. It is positively skewed. It is negatively skewed 8. When statisticians analyze sample data in order to draw conclusions about the characteristics of a population, this is referred to as: Data summarization Data analysis Descriptive statistics Statistical inference 9. A research firm conducted a survey to determine the mean amount steady smokers spend on cigarettes during a week. A sample of 64 smokers revealed that = $20 and S = $5. What is the 95% confidence interval for ? $18.60 to $21.40 $18.78 to $21.23 18.37 to 21.63 18.16 to 21.84 10. The ages of all the patients in the isolation ward of the hospital are 38, 26, 13, 41, and 22. What is the population standard deviation? 6.92 10.33 15.85 9.26 11, The first card selected from a standard 52-card deck was a king. If it is returned to the deck, what is the probability that a king will be drawn on the second selection? 1/13 or 0.077 12/13 or 0.923 1/4 or 0.25 1/3 or 0.33 12. 12 An auditor for American Health Insurance reports that 20% of policyholders submit a claim during the year. 15 policyholders are selected randomly. What is the probability that at least 3 of them submitted a claim the previous year? .602 .250 .200 .708 13. Sales at a fast-food restaurant average $6,000 per day. The restaurant decided to introduce an advertising campaign to increase daily sales. To determine the effectiveness of the advertising campaign, a sample of 49 days of sales was taken. It found that the average daily sales were $6,400 per day. From past history, the restaurant knew that its population standard deviation is about $1,000. The value of the test statistic is _______. 6,400 2.8 1.96 6,000 14. What is the range of values for a coefficient of correlation? 0 to +1.0 Unlimited range -3 to +3 inclusive -1.0 to +1.0 inclusive 15. Which approach to probability assumes that the events are equally likely? Empirical Subjective Classical Mutually exclusive