1) The Cranston Hardware Company is interested in estimating the difference in the mean purchase for...
a) Find a 95% confidence interval for estimating the difference in mean exposure to radioactivity for the two years. b) Perform a hypothesis test to test the claim that radioactivity has been reduced. What are your hypotheses? What is your test statistic? 4. (10 pts) A study is conducted to estimate the difference in the mean occupational exposure to radioactivity in computer science students in the years 2000 and 2008. These data based on independent samples of students for the...
Suppose a researcher is interested in answering the following question: Is there a difference between the mean body temperatures for men and women? He collects data on body temperature and gender from a random sample of 130 men and women. The data collected is shown in the table below. Calculate a 95% confidence interval to answer the researcher’s question. Mean Standard Deviation Sample Size Males 98.105 0.699 65 Females 98.394 0.743 65 (A) Are the criteria for the t-distribution met?...
A researcher is interested in estimating the mean cholesterol level in men. Based on a simple random sample of 54 men, the 95% confidence interval for the population mean μ was 189.9 < μ < 210.1 A. If 100 different samples of size 54 are selected, and based on each sample, a confidence interval was constructed, exactly 95 of these confidence intervals would contain the true value of μ. B. If many different samples of size 54 are selected and,...
A shoe company is interested in estimating the average amount customers spent at their new store in a mall. A sample of 25 customers produced a mean spending of RM150 and with standard deviation of RM20. A 95% confidence interval for the true mean is: A. RM150 ± 164.80 C. RM150 ± 8.26 B. RM150 ± 8.24 D. RM150 ± 165.12
A meteorologist in Jenkins county is interested in estimating the average annual rainfall of the region. The annual rainfall is assumed to follow a normal distribution. She takes a sample of last 10 years and obtains an alterage annual rainfall of 39.5 inches and a standard deviation of 3.8 inches. Estimate a 95% confidence interval for the population mean. 39.5 +/-
A student researcher compares the heights of men and women from the student body of a certain college in order to estimate the difference in their mean heights. A random sample of 6 men had a mean height of 68.3 inches with a standard deviation of 1.68 inches. A random sample of 11 women had a mean height of 63.2 inches with a standard deviation of 1.67 inches. Determine the 95% confidence interval for the true mean difference between the...
7. A student researcher compares the heights of men and women from the student body of a certain college in order to estimate the difference in their mean heights. A random sample of 14 men had a mean height of 67.7 inches with a standard deviation of 3.06 inches. A random sample of 17 women had a mean height of 64.7 inches with a standard deviation of 1.97 inches. Determine the 90% confidence interval for the true mean difference between...
0 pts A large Midwestern university is interested in estimating the mean time that students spend at the student recreation center per week. A previous study indicated that the standard deviation in time is about 25 minutes per week. If the officials wish to estimate the mean time within ± 4 minutes with a 90 percent confidence, what should the sample size be? 106 Can't be determined without the sample mean. 105 105.685
A researcher is interested to see if there is an average difference in the age of male v. female CJ381 students. To examine this, she conducts a t-test. The SPSS output is shown below: Group Statistics sex N age in years 224 HL Mean 19.83 256 19.86 female male Std. Deviation 2.063 1.965 Std. Error Mean 138 123 Independent Samples Test Levene's Test for Equality of Variances t-test for Equality of Means sia Mean Difference 95% Confidence interval of the...
7 A car manufacturer is interested in estimating the true mean fuel consumption in real-world city driving for one of its new models. 10 new randomly selected cars are driven for a tank, and it is found that the sample mean fuel consumption is 9.4 l/100k, with a sample standard deviation of s = 0.343. Suppose the manufacturer wishes to construct a confidence interval for mu, the true mean fuel consumption for this model under these conditions. a) What is...