Math Test 4
If 100 out of 400 students in the population prefer rock, approximately how many students would we expect to prefer rock in a random, representative sample of 12 students?
3
If 100 students participated in a good, representative, random sample and results showed that 40 of the students preferred the color blue, then the relative frequency of blue is _________.
40 %
In order to _____________, we must understand and allow for natural and random sources of variability.
Generalize
_______ is the process of extending results from a sample to a population.
Generalizing
In the Strength of Association video, we can use______ in Word to plot a scatterplot of the relationship between 2 variables.
Insert - Chart - XY Scatter
Measures of_________ give the statistical _______ of the relationship between variables of interest.
association,strength
A strong negative correlation of -.90 indicates that as one variable decreases, the other variable ________.
decreases
If a teacher divides her class into 4 parts and practices different teaching methods on each group to see which group performs better on standardized tests, this is called an ______study.
experimental
The correlation coefficient will tell us whether or not the variables _______, it will not tell us _____________.
have a linear relationship, causation
The height vs. arm span example was an ____study since we did not change existing conditions.
observational
If a good random sample is taken, representative of the population, then sample statistics can be used to estimate _____________________.
population parameters
A __________ is a condition that is imposed on individuals or subjects in the experiment.
treatment
When an "eyeball" line is drawn on a scatterplot of two variables, this line can be used to predict the y value, given the x value. To do this, a _______ line is drawn up from the x value until it intersects the eyeball line. Then a ________line is drawn to the y axis from this point of intersection.
vertical, horizontal
In the word length example, we will have variability _______when we sample words in 3rd grade books.
within the group
When an "eyeball" line is drawn on a scatterplot the equation of the line can be determined by finding 2 points on the line. If the 2 points are (3, 9) and (2, 7) then the equation of the line is ___________.
y = 2x +3
Variability is not present within a sample.
False
The correlation coefficient is a value between ________ that indicates how strongly the two variables are related.
-1 and 1
Use Excel to find whether there is a statistically significant difference between the test scores of two different statistics classes. Class one: 100,99,99,90,90,90,89,89,88,87,79,79,77,69,68,59,58,0 and Class two: 100,93,96,93,93,93,93,93,96,86,89,82,86,68,82,82,89,89,79,82 The t-test score is _______.
.10
Use the CORREL function in Excel to find the correlation coefficient of the scores: 100 24 96 25 96 23 93 25 93 25 93 24 93 22 93 25 93 22 89 22 89 25 89 0 86 23 86 25 82 0 82 23 82 24 82 19 79 19 68 19 The correlation coefficient is ______
.30
If 10 out of 200 students in the population prefer jazz, approximately how many students would we expect to prefer jazz in a random, representative sample of 20 students?
1
If 80 out of 400 students in the population prefer rap, approximately how many students would we expect to prefer rap in a random, representative sample of 100 students?
20
Variability is eliminated from a randomized comparative experiment, such as a medical trial.
False
Who's the best???
CONNOR :-))))
Variability in a randomized comparative experiment can be introduced by __________ causes such as inherent differences in individuals.
Natural
Variability in a randomized comparative experiment can be introduced by __________ causes such as random selection into a treatment group.
Random
_________are formed by dividing the frequency in each column by the total sum.
Relative frequencies
A scatterplot can be used to model the linear association of 2 variables, such as height and arm span.
True
In a randomized comparative experiment such as a medical trial, variability is introduced due to individual responses to a treatment.
True
It is important to distinguish between association studies and experiments.
True
Variability is present from sample to sample.
True