Chapter 1
How many types of variables are there?
Two: Qualitative and Quantitative
Unimodal means a curve has:
One mode, or peak
What percentage of data does the empirical rule say is between 1 standard deviation, 2 standard deviations, and 3 standard deviations for bell-shaped, symmetric curves?
68%, 95%, and 99.7%
True or false: the closer a correlation coefficient is to 0 the stronger the relationship between x and y.
False.
If a sample is taken involving the number of square feet in houses, is the variable quantitative or qualitative?
If quantitative, is it discrete or continuous?
If qualitative, is it ordinal or nominal?
Quantitative - Continuous
Distributions of data (curves, histograms, etc) are symmetric if:
The right and left halves of the distribution are approximately mirror images of one another.
To find the mean, median, standard deviation, and five minimum among other numbers what calculator steps do we follow?
1. Enter data into list 1 (Stat - enter)
2. Stat - Calc - 1-var-stats
To get the correlation coefficient from your calculator you:
1. Enter data into list 1 and list 2 (Stat - edit)
2. Stat - calc - LinReg (a+bx or ax+b)
State the different sampling methods.
Simple random sample Convenience
Stratified Cluster Systemative
If a distribution is skewed ______ then the mean is greater than the median, and vice versa.
Right
Formula for z-score:
Z= observed - mean/standard deviation
Draw a scatterplot with a correlation coefficient of -0.78.
Describe the scatterplot
To be answered by administrator
What is the difference between stratified and cluster sampling?
In stratified, the population is separated into categories and members from each category are sampled, whereas in cluster sampling the population is separated into categories and different categories are selected to be sampled in their entirety.
Refer to drawing on board to answer the following question:
Is the curve on the board unimodal, bimodal, or uniform?
Is the curve symmetric, skewed left, or skewed right?
Unimodal, skewed left.
What percentage of data lies between 73 and 101 if the mean is 80 and the standard deviation is 7?
85.85%
Given the following data, find the regression equation for the relationship between the acreage of a piece of real estate and the price.
Acres of Land: {0.5} {1.5} {4.45} {7} {9} {14} {28.7} {33}
Real Estate Price: {250k} {530k} {300k} {265k} {750k} {1890k} {2600k} {2300k}
y = 195.45 + 74.59x
A library wants to survey its customers about whether it should invest in more eBooks or more physical books. What type of sampling are they enacting in each of the following methods?
a. They have people pick which genre they mostly read and then ask a few people from each genre whether they would like more eBooks or physical books.
b. They compile a list of all library card owners and sample every 20th person on the list.
c. They ask each person checking out one day what they think about eBooks vs. physical books.
a. Stratified
b. Systematic
c. Convenience
In the distribution on the board, is the mean higher than, equal to, or less than the median?
To be answered day of.
Given the following data points, give the five number summary and the upper and lower boundaries:
40 47 43 42 47 34 38 48 48 40 45 49
Min = 34 Q1 = 40 Med = 44 Q3 = 47.5 Max = 49 Lower B: 28.75
Upper B: 58.75
Given the following data, what is the predicted value for a piece of real estate with 3.2 acres?
What is the residual for the piece of land which has 4.45 acres?
Acres of Land: {0.5} {1.5} {4.45} {7} {9} {14} {28.7} {33}
Real Estate Price: {250k} {530k} {300k} {265k} {750k} {1890k} {2600k} {2300k}
434.14 k
-227.38k