Determine whether a normal sampling distribution can be used. If can be used, test the claim about the difference between two population proportions

$$p _ { 1 }$$

and

$$p _ { 2 }$$

at the level of significance

$$\alpha$$

. Assume the samples are random and independent. Claim:

$$p _ { 1 } < p _ { 2 }; \alpha = 0.05$$

. Sample statistics:

$$x _ { 1 } = 471, n _ { 1 } = 785$$

and

$$x _ { 2 } = 372, n _ { 2 } = 465$$

According to the Bureau of Labor Statistics (BLS), there were 38,000 desktop publishing jobs in the United States in 2000. The BLS projects that there will be 63,000 desktop publishing jobs in 2010.

a. Using the BLS data, find the number of desktop publishing jobs as a linear function of the year.

b. Using your model, in what year will the number of desktop publishing jobs first exceed 60,0000?

Here are the annual numbers of deaths from floods in the United States from 1995 through 2015:

80, 131, 118, 136, 68, 38, 48, 49, 86, 82, 43, 76, 87, 82, 56, 103, 113, 29, 82, 38, 176

Find these statistics:

a) mean

b) median and quartiles

c) range and IQR

Chemical analyses of 1599 red and 4898 white Italian wines showed the next summary statistics for $\mathrm{pH}$ (a measure of acidity):

Is there a difference in $\mathrm{pH}$ between red and white wines?

d) Is there a significant difference in $\mathrm{pH}$ ?

According to a recent U.S. Bureau of Labor Statistics report, the proportion of married couples with children in which both parents work outside the home is 59%. You select an SRS of 50 married couples with children and let $\hat{p}=$ the sample proportion of couples in which both parents work outside the home. Calculate the mean and the standard deviation of the sampling distribution of $\hat{p}.$

In paragraph 7, the author lists the known quantities of satellites for Jupiter and Saturn with the purpose of A. increasing the likelihood that the new planets' will have satellites. B. impressing the audience with statistics. C. describing how Jupiter and Saturn are unlike the discovered planets. D. providing an example that supports the new planets' having satellites. E. emphasizing the argument for space exploration.

The index of deflated turnover for retail trade reveals the activity in volume of the retail trade sector. The United Nations Statistics Division reports Retail trade deflated sales/turnover (seasonally adjusted) with $2005=100$. The data file holds this index for 43 countries for the years 2007-2010.

d) What percentage of the variability in the 2010 Index is accounted for by the regression model?

In an introductory statistics course, x = midterm exam score and y = fina l exam score. Both have 1n ean = 80 and standard deviation = 10. The correlation between the exam scores is 0.70.

a. Find the regression equation .

b. Find the predicted final exam score for a student with midterm exam score = 80 and another with midterm exam score = 90.

Phytopigments are a marker of the amount of organic matter that settles in sediments. Phytopigment concentrations in deep-sea sediments collected world-wide showed a very strong right-skew. Of these two summary statistics, 0.015 and 0.009 grams per square meter of bottom surface, which one is the mean and which one is the median? Explain your reasoning.

Chemical analyses of 1599 red and 4898 white Italian wines showed the next summary statistics for $\mathrm{pH}$ (a measure of acidity):

Is there a difference in $\mathrm{pH}$ between red and white wines?

a) Write the null and alternative hypotheses

Imagine you left your statistics textbook and calculator in your locker, and you need to simulate a random phenomenon that has a 25% chance of a desired outcome. You discover two nickels in your pocket that are left over from your lunch money. Describe how you could use the two coins to set up your simulation.

Determine whether a normal sampling distribution can be used. If it can be used, test the claim about the difference between two population proportions

$$p _ { 1 }$$

and

$$p _ { 2 }$$

at the level of significance

$$\alpha$$

. Assume the samples are random and independent. Claim:

$$p _ { 1 } < p _ { 2 }; \alpha = 0.05$$

. Sample statistics:

$$x _ { 1 } = 86, n _ { 1 } = 900$$

and

$$x _ { 2 } = 107, n _ { 2 } = 1200$$

A sample of 25 observations provides the following statistics:

$$s_x=2, \quad s_y=5, \quad \text { and } \quad s_{x y}=-1.75$$

a. Calculate and interpret the sample correlation coefficient $r_{x y}$.

b. Specify the competing hypotheses in order to determine whether the population correlation coefficient differs from zero.

c. Make a conclusion at the 5% significance level.

A statistics practitioner would like to conduct a survey to ask people their views on a proposed new shopping mall in their community. According to the latest census, there are 500 households in the community. The statistician has numbered each household (from 1 to 500), and she would like to randomly select 25 of these households to participate in the study. Use Excel to generate the sample.