Statistics and Probability Answers

& If historical time series data is very limited, what type of forecasting approach would be useful?& & & & & & & & & & & & & & &
& & & & & & & & & & & & & & & & & &
& & & a. Moving average& & & & & & & & & & & & & & &
& & & b. Delphi method& & & & & & & & & & & & & & &
& & & c. Double exponential smoothing& & & & & & & & & & & & & & &
& & & d. Regression model with seasonality

What formula would be used for a within-participants design in statistics?

Music No Music
17 17
16 18
15 17
16 17
18 19
18 18

a. What statistical test should be used to analyze the data?

b. Is this a one- or two tailed test?

c. Identify H0 and Ha for this study.

d. Conduct the appropriate analysis. Should H0 be rejected? What should the researcher conclude?

e. Calculate the 95 confidence interval.

The mean return for a random sample of 33 mutual funds is 14.93 percent with a standard deviation of 9.57. Test the null hypothesis: H0: mu = 15% at α = 0.05

A bottled water company sells spring water for water coolers. The company filters the water to keep the mean percent of impurities below a maximum level. To determine if it was meeting this requirement, it selected a random sample of 27 bottles, opened them, and analyzed them for impurities. The sample standard deviation was 0.00161%. The company knew the data were normally distributed, but it did not know the distribution’s population standard deviation. It calculated a confidence interval to be (0.003209, 0.011191). Which of the following is closest to the level of this confidence interval?

Two Die, are rolled, what is the probability that the total number will be double numbers?

x f
5 5
15 7
25 11
35 16
45 13
55 7
65 4
75 2

mean deviation,variance, standard deviation, coefficent of variance

In eight throws of a dice ,5 or 6 is considered success.Find mean number of successes and standard deviation.

The following table gives the distributions
of marks in a class of 65 students :

Marks No. of students
0 —4 10
4 — 8 12
8 —12 18
12 —16 10
16 —20 5
20 — 24 4
24 and above 6

Calculate mode and semi-inter quartile
range.(please include details)

In 1983, a random sample of 1000 scientists included 212 female scientists. A similar random sample of scientists in 1990 included 272 women. Do these figures indicate an increase in the population proportion of scientists who are women?