An investigator wants to test whether exposure to secondhand smoke before 1 year of life is associated with development of childhood asthma (defined as asthma diagnosed before 5 years of age). Give two possible study designs.

nitraiddQ
2020-11-01
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liingliing8

Answered 2020-11-02
Author has **95** answers

Step 1

Two study design can be used for this scenario:

(i) Two-Sample Independent t-test:

This test is used because:

(a) It is very easy to interpret the output of independent samples.

(b) A small number of subjects for independent t-test samples are required.

(c) T-test enables us to compare the average values of the two data set samples and determine whether the sample subjects come from the same population.

(d) The test gives you all the information you need to know about the population.

Step 2

(ii) Two samples Paired t-test:

This test is used because:

(a) T-test repeated measure design results in small effects since the amount of error from samples is very small.

(b) Only one group is available for testing and this can result in less noise of data.

(c) Only one value from each subject is needed, it requires values of subjects from the two sample groups on a quantitative variable.

(d) Standard software programs that support statistical functions like Microsoft Excel can be used to calculate t-test data.

Two study design can be used for this scenario:

(i) Two-Sample Independent t-test:

This test is used because:

(a) It is very easy to interpret the output of independent samples.

(b) A small number of subjects for independent t-test samples are required.

(c) T-test enables us to compare the average values of the two data set samples and determine whether the sample subjects come from the same population.

(d) The test gives you all the information you need to know about the population.

Step 2

(ii) Two samples Paired t-test:

This test is used because:

(a) T-test repeated measure design results in small effects since the amount of error from samples is very small.

(b) Only one group is available for testing and this can result in less noise of data.

(c) Only one value from each subject is needed, it requires values of subjects from the two sample groups on a quantitative variable.

(d) Standard software programs that support statistical functions like Microsoft Excel can be used to calculate t-test data.

asked 2021-01-31

The centers for Disease Control reported the percentage of people 18 years of age and older who smoke (CDC website, December 14, 2014). Suppose that a study designed to collect new data on smokers and Questions Navigation Menu preliminary estimate of the proportion who smoke of .26.

a) How large a sample should be taken to estimate the proportion of smokers in the population with a margin of error of .02?(to the nearest whole number) Use 95% confidence.

b) Assume that the study uses your sample size recommendation in part (a) and finds 520 smokers. What is the point estimate of the proportion of smokers in the population (to 4 decimals)?

c) What is the 95% confidence interval for the proportion of smokers in the population?(to 4 decimals)?

a) How large a sample should be taken to estimate the proportion of smokers in the population with a margin of error of .02?(to the nearest whole number) Use 95% confidence.

b) Assume that the study uses your sample size recommendation in part (a) and finds 520 smokers. What is the point estimate of the proportion of smokers in the population (to 4 decimals)?

c) What is the 95% confidence interval for the proportion of smokers in the population?(to 4 decimals)?

asked 2022-06-22

Suppose a line goes through the points $A=({x}_{1},{y}_{1})$ and $B=({x}_{2},{y}_{2})$. One can easily check (as I did today while doodling) that

$b=-\frac{{x}_{1}{y}_{2}-{x}_{2}{y}_{1}}{{x}_{2}-{x}_{1}}$

where $b$ is the y-coordinate of the $y$-intercept. This can be written more suggestively as

$\begin{array}{}\text{(1)}& b=-\frac{det(A,B)}{\mathrm{\Delta}x}\end{array}$

The presence of det(A,B) suggests a geometrical interpretation, but I couldn't think of one. This reminds me of Cramer's Rule, but I couldn't make that connection explicit either.

$b=-\frac{{x}_{1}{y}_{2}-{x}_{2}{y}_{1}}{{x}_{2}-{x}_{1}}$

where $b$ is the y-coordinate of the $y$-intercept. This can be written more suggestively as

$\begin{array}{}\text{(1)}& b=-\frac{det(A,B)}{\mathrm{\Delta}x}\end{array}$

The presence of det(A,B) suggests a geometrical interpretation, but I couldn't think of one. This reminds me of Cramer's Rule, but I couldn't make that connection explicit either.

asked 2021-09-30

a. The range of WR scores that would contain about 95% of the scores in the drug dealer sample.

Given info:

The data have mount-shaped, symmetric distribution.

$n=100,\stackrel{\u2015}{x}=39,s=6$ .

b. The proportion of scores that lies above 51.

c. The range of WR scores that contain nearly all samples of drug dealer sample.

Given info:

The data have mount-shaped, symmetric distribution.

b. The proportion of scores that lies above 51.

c. The range of WR scores that contain nearly all samples of drug dealer sample.

asked 2021-12-02

A university asked its applicants to write a short essay for its entrance test. Based on their gathered data, it was found out that two out 10 students did not make grammatical mistakes, three out of 10 students made a grammatical mistake, four out of 10 students made two mistakes, and one out of 10 made three grammatical mistakes. What is the average number of grammatical mistakes made by the students in the essay?

asked 2021-12-10

Marriage Prospects Data released by the Cense Bureau in 1986 indicated the likelihood that never married women would eventually marry. The data indicated that the older the women, the less the likelihood of marriage. Specifically, two statistics indicated that women who were 45 and never married had an 18 percent chance of marriage and women 25 years old had a 78 percent chance of marriage. Assume that linear fit to these two data points provides a sonable approximation for the function p-f(a), where p equals the probability of marriage and aequals the age of a no married woman

(a) Determine the linear function pfla

(b) Interpret the slope and p intercept

(a) Determine the linear function pfla

(b) Interpret the slope and p intercept

asked 2021-05-04

For each topic, decide how a scatterplot of the data would likely look. Explain your reasoning. the price of an apple at a grocery store and the price of a peach at a farmers' market

asked 2021-02-26

Consider two normal distributions, one with mean-4 and standard deviation 3, and the other with mean 6 and standard deviation 3. Answer true or false to each statement and explain your answers.

a. The two normal distributions have the same spread.

b. The two normal distributions are centered at the same place.

a. The two normal distributions have the same spread.

b. The two normal distributions are centered at the same place.