Intro, Vocabulary, and Rates
We use frequency distribution for these three types of variable measurement.
Measures of central tendency tell us this.
What's at the center of the data
Measures of variability tell us this.
How spread out the data are
You shoot at a target 20 times. You make 7 shots and miss 13. p (make) =
.35
If a researcher hypothesizes that people exposed to stressful life events will score higher on a depression screening, then _____ is the researcher's independent variable and _____ is the researcher's dependent variable.
stressful life events; depression score
The equation for proportion is p=
f/n
We use measures of central tendency for these two types of variable measurement.
numeric discrete and numeric continuous
We use measures of variability for these two types of variable measurement.
numeric discrete and numeric continuous
You have 12 green marbles and 13 white marbles. You remove a marble and do not put it back, and then you remove another marble. If you pick a white marble in trial 1, the probability of picking a white marble in trial 2 =___
.500
A researcher interviews 1,000 Wisconsinites to find out whether they agree or disagree with a new law. This is the unit of analysis.
individuals
You are making a frequency distribution table for the hometown of 6 survey respondents: Milwaukee, Milwaukee, Madison, Milwaukee, Madison, Green Bay. Your first column lists Hometown (X):
Milwaukee
Madison
Green Bay
This is what goes in the second column of your table.
f
3
2
1
This is the median for the following unemployment rates: 5.6, 7.4, 6.1, 4.2
5.85
You're calculating variance. You've just completed step 3, squaring all of your answers from the previous step. This is what you do with your squared answers.
add them
You make a probability tree showing the probability of pulling black and white marbles across two trials. If you get the results listed below, the probability that you pulled at least one white marble = ____.
P(WW) = .296
P(WB) = .256
P(BW) = .256
P(BB) = .192
.808
You are making a frequency distribution table for students in each grade at a high school. There are 204 freshman, 186 sophomores, 194 juniors, and 250 seniors. p for juniors =
.2326
This is the mean for the following unemployment rates: 5.6, 7.4, 6.1, 4.2
5.83
If the standard deviation is 4.32, then the variance is:
18.66
You have 4 pink marbles and 4 red marbles. You pull one marble, put it back, and pull another. P (RR) =
.250
A state with a population of 3,118,102 had 104 homicides in the past year. This is the homicide rate per 100,000 population.
3.34
You are making a frequency distribution table for the number of students in 8 classrooms at a particular school. The number of students in the classrooms are as follows: 20, 25, 15, 30, 20, 20, 25, 15. This is what goes in your first column (left-most column) of your table.
Number of students (X)
15
20
25
30
You have the following unemployment rates: 5.6, 7.4, 6.1, and 4.2. If you replace 7.4 with 20.3, this is what happens to the median and the mean. The median will ____ (increase/decrease/stay the same) and the mean will (increase/decrease/stay the same).
stay the same; increase
You're calculating variance for unemployment rates in 12 cities. You've just completed steps 1-4 and you have the sum of your squared answers. You put that number in the numerator and you put ____ in the denominator.
11
You have 12 green marbles and 13 white marbles. You remove a marble and do not put it back, and then you remove another marble. p (GG) = ____
.220