Statistical Variables

Which of the following are parameters? Select all that apply.

• 75% of the students at North High School voted for Lucy

• The total collected at a fundraiser was $5, 281

• The mean height of students at one table in the cafeteria is 1.3 m.

• Ten out of 25 random people surveyed chose "red."

Fenyang is comparing rooms at a conference center. Here is some data he collected.

This data set contains:

• 4 variables, 2 of which are quantitative

• 4 variables, 3 of which are quantitative

• 3 variables, 2 of which are quantitative

• 3 variables, 3 of which are quantitative

The dot plots show how long it took students in Mr. Chauncey's two science classes to finish their science homework last night. Find the means to make an inference about the data.

• The 1st period mean is 35. The 2nd period mean is 38.75. On average, it took students in the 1st period class slightly longer to finish their homework than it did the students in the 2nd period class.

• The 1st period mean is 38.75. The 2nd period mean is 35. On average, it took students in the 1st period class slightly longer to finish their homework than it did the students in the 2nd period class.

• The 1st period mean is 35. The 2nd period mean is 38.75. On average, it took students in the 2nd period class slightly longer to finish their homework than it did the students in the 1st period class.

• The 1st period mean is 38.75. The 2nd period mean is 35. On average, it took students in the 2nd period class slightly longer to finish their homework than it did the students in the 1st period class.

Match the following

• Confounding Variable

• A variable whose values are used to explain or

  predict corresponding values for the response variable.

• Independent Variable

• Independent Variable symbol

• Dependent Variable

• Dependent Variable symbol

• x

• A variable that is related to the explanatory variable and influences the response variable and may create a false perception of association between the two.

• y

• A variable whose values are explained or predicted by the explanatory variable

The number of accidents in a city during 2010 is

• Discrete variable

• Continuous variable

• Qualitative variable

• Constant

What is a quantitative variable that could have an infinite number of values?

• categorical variable

• qualitative variable

• discrete variable

• continuous variable

A variable (or response variable) is

• a characteristic of interest about each individual element of a population or sample

• a characteristic that is irrelevant to the collection of the data

• a characteristic that changes when the data is collected

• a characteristic or trait that will be ignored in a sample population

Litzy collects data from a random sample of 7th graders. Out of 40 respondents, 7 attend afterschool programs. Of the 200 7th graders attending Litzy's school, how many would be expected to attend afterschool programs?

• 14 7th graders

• 28 7th graders

• 35 7th graders

• 42 7th graders

The dot plot shows a random sample of the number of fish caught and released by 30 participants during a two-day fishing tournament. Select the inference that can be made based on the data collected.

• On average, most participants caught and released 5 or more fish.

• More participants caught 6 fish than any other number.

• The same participants who caught and released 1 fish the first day caught and released 1 fish on the second day.

• On average, participants caught and released more fish on Day 2.

If you are able to determine a direct correlation between two variables but can identify one or more confounding variables, can you make an inference between the two correlated variables?

• Yes

• No

• Sometimes