In 2006, 12.1% of all live births in the United States were to mothers under 20 years of age. A sociologist claims that births to mothers under 20 years of age is decreasing. The sociologist conducts a simple random sample of 43 births and finds that 5 of them were to mothers under 20 years of age. Test the sociologist's claim at the a = 0.05 level of significance. Preliminary: a. Is it safe to assume that n < 5% of all mothers under 20 years of age in the United States? Yes No b. Verify np(1 - p) 2 10. Round your answer to one decimal place. пр(1 — р) - c. Since np(1 p) < 10, we should use which distribution to obtain the p-value? uniform distribution binomial distribution exponential distribution Note: Without being given that the population is normally distributed, and that np(1 – p) < 10 , we cannot assume normal distribution and are required to use the binomial distribution. Test the claim: a. What are the null and alternative hypotheses? Ho: ? V ? V Ні: ? V ? V b. Based on the hypotheses, calculate the p-value using the binomial distribution. Round to four decimal places. p-value = c. Make a decision. Select an answer d. Make a conclusion regarding the claim. Select an answer V that the population of births to mothers under 20 years of age in the United States is decreasing.

A hypertension trial is mounted, and 12 participants are randomly assigned to receive either a new medication or a placebo. Each participant takes the assigned medication, and the participants’ SBP is recorded after 6 months on the assigned medication. The data are shown in Table 7–9. Is there a difference in mean SBP between treatments? Run the appropriate test at a = 0.05. Placebo New Medication 134 114 143 117 148 121 142 124 150 122 160 128

The following table shows the ethnic origins of two random samples of students from a Canadian university, one from 2012 and the other from 2022: European 2012 2022 African Asian 308 58 52 364 100 58 Note: Canadian born students are classified according to their ancestry. (a) What would be an appropriate test to check if there has been an overall change in the distribution of ethnic origins among the student population of that university between 2012 and 2022? Justify your answer. ] Other 22 38 (b) Based on your answer in (a) above, test whether there has been an overall change in the distribution of ethnic origins among the student population of that university between 2012 and 2022. Use a 5% significance level and show your detailed manual calculations and all the steps of your hypothesis test (hypotheses, significance level, expected cell frequencies (rounded to 1 decimal), test statistic, decision criteria, critical value and p-value, conclusion with justification). (Manual…

The owner of Maumee Ford-Volvo wants to study the relationship between the age of a car and its selling price. Listed below is a random sample of 12 used cars sold at the dealership during the last year.  Car Age (years) Selling Price ($000) 1 11 12.1 2 8 10.5 3 14 5.7 4 17 4.9 5 9 5.0 6 8 13.4 7 10 10.5 8 14 9.0 9 13 9.0 10 17 4.5 11 6 12.5 12 6 11.5   Click here for the Excel Data Filea. Determine the regression equation. (Negative amounts should be indicated by a minus sign. Round your answers to 3 decimal places.) a= b=   Estimate the selling price of an 7-year-old car (in $000). (Round your answer to 3 decimal places.) Interpret the regression equation (in dollars). (Round your answer to the nearest dollar amount.)

According to the U.S. Department of Transportation’s Air Travel Consumer Report, the nation’s 12 largest airlines recorded an on-time arrival percentage of 77.4% in 2001. Of interest is to estimate the mean delay time for the 22.6% of all flights that did not arrive on time during 2013. A simple random sample of 28 late arriving flights was selected, and the mean delay time of this sample of 28 flights was 14.2 minutes, with a sample standard deviation of s= 6.4 minutes. Use this information to calculate and interpret a 98% confidence interval for the mean delay time for all flights that did not arrive on time during 2013.

The price of a share of stock divided by the company's estimated future earnings per share is called the P/E ratio. High P/E ratios usually indicate "growth" stocks, or maybe stocks that are simply overpriced. Low P/E ratios indicate "value" stocks or bargain stocks. A random sample of 51 of the largest companies in the United States gave the following P/E ratiost. 9 20 11 35 19 13 15 21 29 53 16 26 21 14 21 27 10 12 47 14 40 18 60 72 33 14 8 49 5 16 8 19 12 31 67 51 26 18 17 20 19 13 25 23 27 44 20 27 19 18 32 (a) Use a calculator with mean and sample standard deviation keys to find the sample mean x and sample standard deviation s. (Round your answers to one decimal place.) (b) Find a 90% confidence interval for the P/E population mean u of all large U.S. companies. (Round your answers to one decimal place.) lower limit upper limit (c) Find a 99% confidence interval for the P/E population mean u of all large U.S. companies. (Round your answers to one decimal place.) lower limit upper…

Fewer young people are driving. In 1995, 63.9% of people under 20 years old who were eligible had a driver's license. Bloomberg reported that percentage had dropped to 41.7% in 2016. Suppose these results are based on a random sample of 1,200 people under 20 years old who were eligible to have a driver's license in 1995 and again in 2016.

2. Jim Miller works in the personnel department for a car company. He is told by his supervisor to investigate the difference in the average number of sick days between blue collar workers and whitecollar workers. So he obtained a random sample of 9 blue collar workers and a random sample of 9 white collar workers. He records the results below.At 10% level of significance, is there sufficient evidence to indicate a difference in mean sick days between blue collar workers and white collar workers.

A recent Gallup Poll interviewed a random sample of 1523 adults. Of these, 868 bought a lottery tickets in the past year. Suppose that in fact (unknown to Gallup) exactly 60% of all adults bought a lottery ticket in the past year. If Gallup took many simple random samples of 1,523 people, the sample proportion who bought a ticket would vary from sample to sample. The sampling distribution would be close to normal with a mean of 0.6 and a standard deviation of___ A)0.4899 B)0.0251 C)0.00016 D)0.0126

. Each member of a large genetics class grows 12 pea plants from an independent pea family. Each family is expected to have 3/4 plants with smooth peas and 1/4 plants with wrinkled peas. a. On average, how many wrinkled pea plants will a student see in her 12 plants? b. What is the standard deviation of the proportion of wrinkled pea plants per student? c. What is the variance of the proportion of wrinkled pea plants per student? d. Predict what proportion of the students saw exactly two wrinkled pea plants in their sample.