Example 11.3 sample mean was found to be Rs 900 and the standard deviation Rs 200. Construct an interval estimate of the nonulation mean with the confidence level of 95.44 per cent. A random sample of 400 firms was taken to find out the average sale per customer. The
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- If the sample mean is 37.7 and population standard deviation is = 9.2 and the sample size is 100 then find the 90% confidence interval.Suppose a researcher wants to test if the average diastolic blood pressure in Irish-Americans is different than the average diastolic blood pressure in the general population. Note that the average diastolic blood pressure in the general population is 70 mmHG. The researcher recruits 30 Irish-Americans into this particular study and then measures each of their diastolic blood pressures (mmHG). The population of this sample has a standard deviation equal to 3.0. What is the two-sided alternative hypothesis? (in words) Group of answer choices The mean is different than 70 The mean is different than 73 The mean is greater than 70 The mean is greater than 73Suppose that a garage samples 21 customers. They find the average time for there oil change is 4,305 miles. Find a 90% confidence interval of the true mean, if the population standard deviation is 1,151.
- On a measure of running speed on a 100 meter dash, students received timed scores ranging from 12 seconds to 24 seconds. The distribution of running times is normative with a mean of 16 seconds. Transferring this ratio data to standard scores for comparison with the results of classes from other departments, the mean score is assigned a standard score of 100 with a standard deviation of 10. From this example, a standard score of 99 would mean the actual value in seconds for an individual would be about a. 16 b. 12 c. 19 d. 24Cotinine levels were measured in a group of non-smokers exposed to tobacco smoke (n =40), the mean of the sample was 60.58 ng/Ml and the standard deviation was 138.08 ng/Ml. Also, cotinine levels were measured in a group of non-smokers not exposed to tobacco smoke(n =40), the mean of the sample was 16.35 ng/mL and the standard deviation was 62.53 ng/mL. Cotinine is a metabolite of nicotine, meaning that when nicotine is absorbed by the body, cotinine is produced. Use a 0.05 significance level to test the claim that non-smokers exposed to tobacco smoke have a higher mean nicotine level than nonsmokers not exposed to tobacco smoke. a)Define the parameter and state null and alternative hypothesis b)Test Statistics c) Critical Value Approach d) ConclusionIn Professor Krugman’s economics course, the correlation between the students’ total scores prior to the final examination and their final‑examination scores is ?=0.5.r=0.5. The pre‑exam totals for all students in the course have mean 280280 and standard deviation 40.40. The final‑exam scores have mean 7575 and standard deviation 8.8. Professor Krugman has lost Julie’s final exam but knows that her total before the exam was 300.300. He decides to predict her final‑exam score from her pre‑exam total. (a) Which of the choices is the least‑squares regression line of final‑exam scores on pre‑exam total scores in this course?
- In Professor Krugman's economics course, the correlation between the students' total scores prior to the final examination and their final‑examination scores is ?=0.5.�=0.5. The pre‑exam totals for all students in the course have mean 280280 and standard deviation 40.40. The final‑exam scores have mean 7575 and standard deviation 8.8. Professor Krugman has lost Julie's final exam but knows that her total before the exam was 300.300. He decides to predict her final‑exam score from her pre‑exam total. © Macmillan Learning (a) What is the slope of the least-squares regression line of final-exam scores on pre-exam total scores in this course? Give your answer to one decimal place. slope: What is the intercept? Give your answer as a whole number. intercept:4. The cost of a daily newspaper varies from city to city. However, the variation among prices remains steady with a standard deviation of 18¢. A study was done to test the claim that the mean cost of a daily newspaper is $1.00. Twelve costs yield a mean cost of 93¢ with a standard deviation of 17¢. Do the data support the claim at the 1% level?The ages of a group of 138 randomly selected adult females have a standard deviation of 17.5 years. Assume that the ages of female statistics students have less variation than ages of females in the general population, so leto= 17.5 years for the sample size calculation. How many female statistics student ages must be obtained in order to estimate the mean age of all female statistics students? Assume that we want 95% confidence that the sample mean is within one-half year of the population mean. Does it seem reasonable to assume that the ages of female statistics students have less variation than ages of females in the general population? The required sample size is (Round up to the nearest whole number as needed.)
- Suppose that Melanie is a researcher who wishes to estimate the mean birthweight of full-term babies in her hospital. What is the minimum number of babies should she sample if she wishes to be at least 90% confident that the mean birthweight of the sample is within 225 grams of the the mean birthweight of all babies? Assume that the distribution of birthweights at her hospital is normal with a standard deviation of 600 g.Researchers wants to determine if low-fat diets or low-carb diets are more effective for weight loss. Suppose 100 people were placed on a low-fat diet and at the end of 3 months the mean weight loss was 10.5 lbs witha standard deviation of 12.5 lbs. There were another 100 people placed on a low-carb diet and at the end of 3 months the mean weight loss was 16.5 lbs with a standard deviation of 10.2 lbs. Does mean weight lossdiffer between the two diets? What are the hypotheses??A researcher wanted to know whether losing one night sleep can affect problem solving. A sample of n = 25 college students was given a problem-solving task at noon on one day and again at noon on the following day. The students were not permitted any sleep between the two tests. For each student, the difference between the first and the second score was recorded: MD = 5 and standard deviation of the difference score was s = 10. Do the data indicate a significant change in problem solving ability? Use a two-tailed test with α = .01. The alternative hypothesis in words is Group of answer choices Problem solving ability improves after losing on night sleep Problem solving ability is reduced after losing one night of sleep There is no significant difference in problem solving ability between the two conditions: before and after losing one night of sleep There is a significant difference in problem solving ability between the two conditions: before and after losing one night of…