Assuming that the population is normally distributed, construct a 90% confidence interval for the population mean, based on the following sample size of n = 7. 1, 2, 3, 4, 5, 6, and 20 Change the number 20 to 7 and recalculate the confidence interval. Using these results, describe the effect of an outlier (that is, an extreme value) on the confidence interval. . . . Find a 90% confidence interval for the population mean, using the formula or calculator. Sus (Round to two decimal places as needed.) Change the number 20 to 7. Find a 90% confidence interval for the population mean, using the formula or calculator. SUS (Round to two decimal places as needed.) What is the effect of an outlier on the confidence interval? O A. The presence of an outlier in the original data increases the value of the sample mean and greatly decreases the sample standard deviation, narrowing the confidence interval. O B. The presence of an outlier in the original data increases the value of the sample mean and greatly inflates the sample standard deviation, widening the confidence interval. O C. The presence of an outlier in the original data decreases the value of the sample mean and greatly inflates the sample standard deviation, widening the confidence interval. O D. The presence of an outlier in the original data decreases the value of the sample mean and greatly decreases the sample standard deviation, narrowing the confidence interval.The data below represents the overall miles per gallon (MPG) of 2008 SUVs priced under $30,000. Complete parts a and b below. 23, 21, 20, 22, 18, 19, 18, 16, 19, 19, 18, 16, 21, 19, 16, 17, 16, 18, 17, 21, 18, 23 . . . a. Construct a 90% confidence interval estimate for the population mean miles per gallon of 2008 SUVs priced under $30,000, assuming a normal distribution. Sus (Round to two decimal places as needed.) b. Interpret the interval constructed in (a). Choose the correct answer below. O A. With 90% confidence, the mean miles per gallon in the sample of 2008 SUVs is the population mean. O B. With 90% confidence, the mean miles per gallon in the population of 2008 SUVs is the sample mean. O C. With 90% confidence, the mean miles per gallon in the population of 2008 SUVs is somewhere in the interval. O D. With 90% confidence, the mean miles per gallon in the sample of 2008 SUVs is somewhere in the interval.19A telecommunications company wants to estimate the proportion of households that would purchase an additional telephone line if it were made available at a substantially reduced installation cost. Data are collected from a random sample of 500 households. The results indicate that 180 of the households would purchase the additional telephone line at a reduced installation cost. Complete parts (a) and (b) below. E> - a. Construct a 95% condence interval estimate for the population proportion of households that would purchase the additional telephone line. Ema (Round to four decimal places as needed.) b. The margin of error e=|j (Round to 3 decimal places as needed.) 6. The critical value for the upper tail is El (Round to 2 decimal places as needed.) d. How would the manager in charge of promotional programs concerning residential customers use the results in (a)? O A. The manager can infer with 95% condence that the proportion of households in the sample that would purchase an additional telephone line is somewhere in this interval. 0 B. The manager can infer with 95% condence that the population proportion of all households that would purchase an additional telephone line is somewhere in this interval. 0 C. The manager can infer that the true population proportion of households that would purchase an additional telephone line is somewhere in this interval 95% of the time. 0 D. The manager can infer that 95% of households would purchase an additional telephone line. In 2010, a survey of 250 homes in a region found that 50 had overestimated market values. Suppose you want to estimate "It" , the population proportion of homes in this region with market values that are overestimated. a. Find p, the point estimate of I. b. Describe the distribution used to find the critical value. c. Find a 99% confidence interval for It. d. Give a practical interpretation of the confidence interval from part c. e. Suppose a researcher claims that it = 0.07. Is the claim believable? Explain. . . . a. The point estimate is . (Type an integer or a decimal.) b. We use the t-distribution to find the critical value for the confidence interval of a proportion. O True O False c. The 99% confidence interval is (Round to two decimal places as needed.) d. Interpret the confidence interval. One can be |% confident that the interval contains the true value of the population proportion Ite. Is the claim that It = 0.07 believable? O A. No. This proportion is beyond three standard deviations of the sample mean. O B. Yes. This proportion is within three standard deviations of the sample mean. O C. No. This proportion is below the lower limit of the confidence interval. O D. Yes. This proportion is within the limits of the confidence interval.Suppose data collected by observers at randomly selected intersections across the country revealed that in a sample of 80 drivers, 20 were using their cell phone. a. Give a point estimate of 7:, the true driver cell phone use rate (that is, the true proportion- or- population porportion- of drivers who are using their cell phone while driving). b. Compute a 90% condence interval for at. c. Give a practical interpretation of the interval, part b. E) a. A point estimate for it is D. b. The 90% condence interval for the population proportion :r. is (ELIE). (Round to two decimal places as needed.) c. Interpret this interval. 0 A. We are condent that 90% of the population use a cell phone while driving. 0 B. There is a 90% percent chance that the population proportion of drivers who use cell phones is outside this interval. 0 C. We are 90% condent that the population proportion of drivers using cell phones is inside this interval. 0 D. We are condent that 90% of the population do not use a cell phone while driving. A team of researchers analyzed the meat from each in a sample of 16 "red snapper" fish fillets purchased from vendors across a region in an effort to estimate the true proportion of fillets that are really red snapper. DNA tests revealed that 12 of the 16 fillets (or 75%) were not red snapper but a cheaper look-alike variety of fish. Complete parts a through c. . . . a. The parameter "It" is the true proportion of fish fillets that are actually red snapper. O True O False b. Explain why it is not appropriate to use a confidence interval in this study. Choose the correct answer below. O A. It is inappropriate because either the number of successes in the sample or the number of failures in the sample is less than 5. O B. It is inappropriate because either the number of successes in the sample or the number of failures in the sample is greater than or equal to 5. O C. It is inappropriate because the expected probability of success is 0.75. O D. It is inappropriate because the sampling distribution is approximately normal. c. The population (true) proportion of fish fillets that are actually red snapper is (Use 2 decimal places rounded.)Find the indicated Z score ( or Z-value). The graph depicts the standard normal distribution with mean 0 and standard deviation 1. *Note- 2 score (or Z-value) is also known as Z critical value. 0.1894 [a] The indicated 2 score is El. (Round to two decimal places as needed in ALL questions.) [b] If the shaded area has value .025, then the Z-value must be D [c] If the shaded area has value .005, then the Z-value must be D [d] If the shaded area has value .115, then the Z-value must be |:|