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The mean per capita income is 17,635 dollars per annum with a standard deviation of 891. What is the probability that the sample mean would differ form the true mean by less than 114 dollars if a sa
A consumer advocate wants to find out if motivational speakers can actually improve people's earning power. He randomly selects a group of 25 people in his city and invites them to participate in a
The standard deviation of the "fat-blocker" sample was 2.5 and the standard deviation of the control group was 2.8. Find the 95% confidence interval for the differences of the means.
Explain why the standard error of the mean decreases with increasing sample size. Provide a mathematical explanation (in words or with equations, whichever you prefer) and a conceptual explanation (
Draw the scatter plot for the variables. Compute the correlation coefficient. Use three decimal places.
Find the value of z that would be used to test the difference between the proportions, given the following. (Use G - H. Give your answer correct to two decimal places.)
Conduct all 6 steps of appropriate statistic. Be sure to label all six steps. Calculate and interpret the effect size for this test. Report the statistics as you would in a journal article.
Find the critical value from Table L for the rank correlation coefficient, given sample size n = 9 and alpha = .05.
A poll of 1000 americans reported that 42% expect to inherit money from their parents. What is the 99% confidence interval of the true proportion of adults who expect to inherit money from their par
A random sample of n = 57 observations produced a mean x = 30.8 and a standard deviation s=2.3 Find a 90% confidence interval for population mean µ.
The lengths of pregnancies are normally distributed with a mean of 268 days and standard deviation of 15 days, if 64 women are selected, find the probability that they have a mean pregnancy between
Two students were asked to rate six different television shows on a scale from 1 to 10 points, with higher values ranking ahead of lower values. Compute the sum of squares of the difference in ranks
Every time you go to a beach for vacation, you take home a little sand to keep as a souvenir. Over your lifetime, you have done this exactly 100 times. On each visit the weight of sand you take home
An economist wants to estimate the mean income for teh first year work for a college graduate who has had the profound wisdom to take a statistics course.
Let A, B, and C be independent random variables, uniformly distributed over [0,4], [0,3], and [0,6] respectively. What is the probability that both roots of the equation Ax2+Bx+C=0 are real?
Find the sum of the positive and negative rank sums as in a Wilcoxon signed-rank test.
Suppose that in one small town the average income is $34,200 with a stansard deviation of $2200. What percent of housholds between $29,800 and $38,600?
The average number of pounds of meat a person consumes a year is 218.8 with a standard deviation of 25 pounds. Assume normal distribution. if a sample of 40 people is selected, what is the probablil
A researcher believes exercise reduces anxiety in women. She identifies a group of women who had not exercised before but are now planning to begin exercising. she gives them a 50- item anxiety inve
Chicken Delight claims that 77 percent of its orders are delivered within 10 minutes of the time the order is placed. A sample of 60 orders revealed that 43 were delivered within the promised time
The mean time between failures (MTBF) is the expected time between a repair and the next failure of a component. MTBF at this time in testing =_______hours
The average wage of a construction worker is $11.76 with a standard deviation of $2.72. Assume normally distributed. What is the probability that a randomly selected worker makes more than $12.55
What is the null hypothesis? Assume a directional hypothesis is warranted. What is the null hypothesis assuming a non-directional hypothesis?