Top of Form

Question 10.5pts

Find a news article that communicates a proportion. Note that it might be expressed as a percentage, since it is often easier for people to put percentages in perspective. If the article has more than one proportion, choose only one proportion to use for this activity.

Remember that a proportion is calculated from binary categorical data, so not all percentages represent proportions (for example, "spending has increased by 2% in the past year" measures the change for a quantitative variable, so this wouldn't work for this activity).

In the text box below, include a web link to the news article.

Flag question: Question 2

Question 20.5pts

What is the value of the sample proportion of interest (p^)? Answer using the number of decimal places that are communicated in the article. If the proportion was expressed as a percentage, divide by 100 to express it as a proportion (a value between 0 and 1).

For example, if the article reported that "53% of children in the US own a smartphone by age 11", thenp^would be equal to 0.53. If the percentage had been reported as 53.2%, thenp^would be equal to 0.532.

Flag question: Question 3

Question 30.5pts

What critical value should you use for a 99% confidence interval? Answer to three decimal places.

Flag question: Question 4

Question 41pts

Calculate the standard error for a 99% confidence interval assuming a sample size of 200. Answer to four decimal places.

Remember that standard error is calculated asSE(p^)=p^q^/n, whereq^=1p^.

We will be assuming a sample size of 200 for this activity since not all news articles will report the sample size that was used.

Flag question: Question 5

Question 50.5pts

Using the unrounded values for the standard error and the critical value, calculate thelower limitof the 99% confidence interval assuming a sample size of 200. Answer as a proportion (between 0 and 1) to four decimal places.

Flag question: Question 6

Question 60.5pts

Using the unrounded values for standard error and the critical value, calculate theupper limitof the 99% confidence interval assuming a sample size of 200. Answer as a proportion (between 0 and 1) to four decimal places.

Flag question: Question 7

Question 71.5pts

Write one sentence to interpret the 99% confidence interval. You can express the limits of the confidence intervals as percentages if you prefer to do so for the interpretation. Be specific about what the confidence interval is estimating.