If 34 out of 109 students replied "yes" to a question, what's the probability of a student saying "no"?
0.688
100
What is the equation for finding a Z-score?
Z = (x-M)/SD
100
If 188 people are sampled and 46 say yes, what's the standard error?
0.0415
100
What is expected value? What's another word for it? Give an example of how it can be used.
Expected value is the long run average of a random variable. It is also known as the mean.
100
Describe a correlation of -0.9 in terms of strength (weak, moderate, or strong) and direction.
Strong, Negative
200
What's the equation for conditional probability?
P(B given A) = P(AandB)/P(A)
200
What is a Z-score?
The distance from the mean in standard deviations.
200
If you have a standard error of 0.0415 and 95% confidence interval, what's the margin of error?
8%
200
What's the equation for expected value (not using the calculator)?
Payout*Probability + Payout*Probability = Expected Value
200
A restaurant's menu items are compared in terms of correlation. Sugar versus Calories have a correlation of 0.25. Sugar versus Protein has a correlation of -0.68. Which has a stronger correlation?
Sugar vs Protein
300
According to a survey done in a local high school, the probability of a student liking basketball was 0.60, liking football was 0.70 and liking both was 0.42. What’s the probability that a student likes football given that she likes basketball?
0.70
300
Given a SD of 8, a mean of 29, and an X value of 43, what's the Z-score? What's the probability of X being greater than 43?
Z = 1.75. Probability = 0.04
300
35 out of 89 respondents answer yes to a question. If the Z-score is 1.8, what's the margin of error?
0.0932
300
A game has an expected payout per customer of $4.50. It costs $3 to play. What's the probability that you make over $2 if the standard deviation is $0.30?
4.7%
300
Which linear regression equation is correlation used in? If correlation is negative, how will this affect this value?
Slope. Slope will be negative.
400
In the same school, the probability that a student likes volleyball is 0.38. The probability that that student likes basketball and volleyball is 0.31. What’s the probability that a student likes basketball given he likes volleyball?
0.816
400
What's the Z-score of a 99% confidence interval?
2.5758
400
If you increase the confidence interval from 95% to 99%, what will happen to the margin of error? Why?
It will increase as well because the Z-score will be bigger.
400
Explain how you find the expected value in your calculator.
Plug in payouts and probabilities in Stat-Edit. Hit Stat-Calc - 1Var Stats. Plug in Pay for X-values and Prob for FreqList. Hit calculate.
400
A student says, "There was a very strong correlation of 1.22 between Sugar and Fat content." Explain the mistake made here.
Correlation cannot be greater than 1.
500
You ask a group of friends of yours to randomly pick a number from a hat - 1 to 10. What's the probability that someone picks a number above 5 given that they pick an even number?
(3/10) / (0.5) = 0.6
500
What is a critical value?
The number of standard errors to move away from the sample statistic to specify an interval that corresponds to the specific level of confidence.
500
If the sample size increases, how will this affect the margin of error? Why?
The margin of error decreases because the standard error decreases.
500
You walk away with $30 if you win BlackJack. $-5 if you lose. What's your expected payout if there's a 25% chance you'll win?
$3.75
500
Why do we find the least squares regression line of the residuals?
It tells us the line that is the closest to the most values.