Stats Help for College-level Students

Hypothesis Testing-Compute the statistical test using the z test and decide what to do with the null.

A sample of 40 households with school-age children in Middletown was randomly selected. The mean length of time was 7.6 years, with a standard deviation of 2.3 years. A sample of 55 households in Brockton revealed the mean length of time was 8.1 years, with a standard deviation of 2.9 years. At the .05 level of significance, can ...continues

Hypothesis Testing-Compute the statistical test using the z test and decide what to do with the null. Also state the Research Hypothesis and the Null Hypothesis.

A sample of 40 observations is selected from one somewhat normal population. The sample mean is 102 and the sample standard deviation is 5. A sample of 50 observations is selected from a second source. The sample mean was 99 and the standard deviation was 6. Conduct a test of the hypothesis using the .04 level of significance.

9 short answer type questions on mean, standard deviation, range, probability, permutation

1. Compute the arithmetic mean for the following data: 8, 2.2, 25, 7, -9, 10, 2, and 5.9. 2. An Embry-Riddle senior performed the same experiment on three groups of subjects (with permission!) and obtained mean scores of 84, 69 and 76. The groups consisted of 13, 31, and 27 subjects respectively. What is the overall mea ...continues

Questions on probability distributions - Binomial, Poisson

1 The Kwik Klean Car Wash loses $30 on rainy days and gains $120 on days when it does not rain. If the probability of rain is 0.15, what is the expected value of net profit? 2. The Newman Construction Company bids on a job to construct a building. If the bid is won, there is a 0.7 probability of making a $175,000 profit and t ...continues

Hypothesis Testing - Compute the statistical test using the t test and decide what to do with the null.

School A states the average number of days missed by each student is 4.0. Office personnel randomly sampled a portion of their attendance records to determine if this claim was accurate. For the previous year, the following data was obtained from the sample group, regarding absences for that year: 4, 4, 3, 2, 6, 8, 7, 1, 9, 3, 1 ...continues

Hypothesis Testing -Compute the statistical test using the t test and decide what to do with the null.

A sample of scores on an examination given to both males and females in QNT 575 are: Males - 72,69,98,66,85,76,79,80,and 77 Females - 81,67,90,78,81,80, and 76 At the .01 level of significance, is the mean grade of the female students higher than that of the males? I need a step by step calculation of the problem. ...continues

Regression: a) Draw a scatter plot of these two variables. Based on this plot only, does it appear that a linear relationship exists between the two variables? b) Compute the correlation coefficient and discuss what it measures. c) Test to determine whether the population correlation coefficient is actually 0, using an alpha level of 0.05. d) Compute the least squares regression equation using money collected as the dependent variable and number of alumni contacted as the independent variable. For this model, compute, and interpret, the following:

The Penrose Consulting Company performs studies for universities that want to raise money through their alumni associations. As part of its work, it recently sampled 18 universities across the United States and determined the number of alumni contacts and the total dollars in gifts received from those alumni during the previous ...continues

Home-Schooled Pupils

Based on this article and your knowledge of college-admissions tests, what variables would you include in a multiple regression model to predict ACT scores? Be certain to include dummy variables (categorical variables). After deciding on the variables to include in the model, explain how stepwise regression, R2adjusted and C ...continues

Find the expected value, variance, standard deviation, and probability.

1) A $25,000 investment in a tract of land may be worth $10,000, $25,000, or $45,000 after one year, the probabilities of these values being 0.25, 0.45, and 0.3, respectively. a) What is the expected value of the investment in one year? b) If your expected return on the investment is the expected present value of the investm ...continues

Statistics

Find the probability and expected value.