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