Stats midterm

To determine who will win autographed footballs, a computer program randomly selects the ticket numbers of 11 people in a stadium filled with people. ____________

srs

When every member of the accessible population has an equal chance of being selected to participate in the study, the researcher is using _________

srs

From the boarding list, randomly select 5 people flying first class and 25 of the other passengers. _____________

stratified

Two hundred people are randomly selected from each of the 50 states for a study of how incomes vary among the states. _____________

stratified

Mr. Marino has compiled a list of 1,348 students in his high school. He has selected a sample of 42 students by choosing every 14th student on this list. ____________

systematic

We need to survey a random sample of the 300 passengers on a flight from Los Angeles to New York. Name each method described below: Pick every 10th passenger as people board the plane. __________

systematic

A nominal variable achieves maximum variation if all of its categories are equally represented (e.g. there are exactly the same numbers of Democrats, Republicans, Green Party members, etc.)

true

A variable consists of the numbers 1, 2, 3, 4, 5. If the number 5 is replaced by the value 20, the standard deviation will increase.

true

Before the standard deviation or variance is calculated, the mean of scores needs to be calculated.

true

Guesses about the value of a number randomly drawn from the jar are more likely to be correct when there is less variability of the numbers in the jar.

true

It is possible for two or more sets of values to have the same standard deviation and variance

true

Like the mean, the standard deviation is sensitive to extreme scores.

true

The MEAN is very sensitive to extreme scores.

true

The MODE and MEDIAN are also considered as one of the averages.

true

Suppose your have scores of 70, 75, and 70 on 100-points quizzes in a statistics class. Is it possible to have a mean of 80 after the fourth and fifth quiz?

yes

Gender

Nominal

Social class

Ordinal

People in immediate family

Ratio

After recording pizza delivery times for two different pizza shops, you conclude that the pizza shop A has a mean delivery time of 45 minutes with a standard deviation of 3 minutes and the pizza shop B has a mean delivery time of 42 minutes with a standard deviation of 20 minutes. If you are risk averse and the pizzas from both shops taste the same, which one would you order from? Select one: a. Pizza Shop A b. Pizza Shop B

a

Which of the following is NOT a true statement about the coefficient of variation? Select one: a. The coefficient of variation is expressed as a percent of the mean and is unitless b. The larger the coefficient of variation, the greater the precision c. The coefficient of variation is used to compare the variability of two different variables

b

Your data set contains a variable on region of residence that contains the following possible response : Northeast, South, Midwest, West, and Pacific Coast. Which of the following measure of central tendency should you use of this variable? a. The mean b. The median c. The mode d. The weighted mean

c.

If a researcher selected five schools at random and then interviewed each of the teachers in those five schools, the researcher used ___________

cluster

In a pre-election poll for a mayoral race, all homes on First, Third, and Fifth Streets are visited. ___________

cluster

The apple harvest from an orchard is collected in 12,000 baskets. An agricultural inspector randomly selects 25 baskets and then checks every apple in each of these baskets for worms. _____________

cluster

BMI

continuous

distance from place to campus

continuous

In trying to learn whether planetary systems are common, astronomers conduct a survey by looking for planets among 100 of the nearest stars.

convenience

Measures of central tendency are

descriptive statistics that identify the best single value for representing a set of data.

# of children in house

discrete

Which of the following variables that you are able to find the mode? a. Marital status i.e. never married, married, divorced, separated, widowed b. Political views i.e. strongly disagree, disagree, neutral, agree, strongly agree c. Annual income bracket d. Ages of owning first house e. All above

e.

It is common for a set of scores to have no variability.

false

The difference between the smallest and largest values of a distribution is called the variance.

false

The standard deviation can never be zero.

false

The standard deviation or variance is a measurement of variability which is appropriate for a nominal or ordinal variable.

false

True or False : Standard deviation or variance can be negative value ; however, it is not common.

false

Two sets of values that have the same mean must also have the same variability

false