Sampling & Experiments
LSRL
Interpretations
Important Things You Need to Know
Probability
Significance Testing
Miscellaneous (Calculator Functions Encouraged)
100
Neither the subject nor those who measure the reponse variable know which treatment a subject received.
What is a double-blind experiment?
100
Description of a linear squares regression line.
What is "Context, Direction, Outliers, Function, and Strength"?
100
Conclusion when P-value = 0.03 and alpha = .05
What is "we reject the null hypothesis, and have convincing evidence to support the alternative hypothesis"?
100
How to identify outliers algebraically
What is any value
less than Q1 - 1.5(IQR) or
more than Q3 + 1.5(IQR)
where IQR = Q3 - Q1?
100
The probability of rolling a fair die three times and getting three fours. (Fraction or decimal)
What is P(rolling three 4s) = P(4)*P(4)*P(4) = P(4)^3 = 1/216 = .0046?
100
Jason reads a report that 80% of US high school students have a computer at home. He believes the proportion is smaller than 0.80 at his large royal high school. Jason chooses an SRS of 60 students and finds that 41 have a computer at home. This type of test is conducted to see if the true proportion of students at Jason’s school who have a computer at home is less than 80%.
What is a "One sample z test for p"?
100
N(12,3);P(X < 8) (any method)
What is normcdf(-9999, 8, 12, 3) = .091?
200
Name the experimental design strategy.
The same group of 32 people blind taste test Coke vs. Pepsi and record their preference. 16 are randomly selected to try Pepsi then Coke, and the other 16 taste Coke then Pepsi. Compare the preference results for both groups.
What is matched pairs?
200
The amount of variability in a given y context that is explained by the LSRL given the x context.
What is the r-squared value?
200
The slope in the least-square regression line, y = 15 - 4x
What is "For every one unit increase in the explanatory variable, there is on average a 4 unit decrease in the reponse variable"?
200
How do you calculate the expected value of a discrete random variable
What is "the sum of the products of the values of x and their respective probabilities?"
200
The probability of pulling a red or queen from a standard deck of cards. (fraction or decimal)
What is P(red or queen) = P(red) + P(queen) - P(red and queen) = 26/52 + 4/32 - 2/32 = 28/52 = .54?
200
One company's bottles of grape juice are filled by machine that is set to dispense an average of 180 milliliters (ml) of liquid. The company has been getting negative feedback from customers about underfilled bottles. To investigate, a quality control inspector takes a random sample of 40 bottles and measures the volume of liquid in each bottle. The mean amount of liquid in the bottles is 179.6 ml and the standard deviation is 1.3 ml. This procedure is conducted to see if there is convincing evidence that the machine is underfilling the bottles.
What is a "one sample t test for μ"?
200
The probability of at least 8 successes in 12 trials given a probability of success of 45%.
What is binomcdf(12, .45, 8,12) = .11?
300
When some groups in the population are left out of the process of choosing a sample
What is undercoverage?
300
The typical distance away the value predicted by the LSRL is away from the actual value.
What is "the standard deviation of the LSRL residuals"?
300
A z-score of -3.45
What is "The data value is 3.45 standard deviations below the mean"?
300
How to determine if two events, A and B, are independent
What is P(B|A) = P(B) or P(A and B) = P(A)P(B)?
300
If IQ distribution is N(100,15), the probability of an IQ at least 110.
What is z=(110-100)/15 = 0.67; table = .7486; p = 1 - .7486 = .2514
or What is normalcdf(110,9999999,100,15) = normalcdf(.667,9999999,0,1) =0.25
300
With Many babies being delivered by planned cesarean section, Mr. Storck’s statistics class hypothesized that there would be fewer younger people born on the weekend. To investigate, they selected a random sample of people born before 1980 and a separate random sample of people born after 1993. In addition to year of birth, they also recorded the day of the week in which each person was born.
What is a "chi square test for homogeneity"?
300
The z* for a 92% confidence interval
What is invNorm(
area = .04
mean (μ) = 0
st. dev (σ) = 1
= -1.75 -> 1.75
400
The population is divided into groups. Some groups are randomly selected and all individuals in the chosen groups are sampled.
What is cluster sampling?
400
Description of a relationship between average March temperatures and the day in April with cherry blossoms bloom, given r = -0.85.
What is "A strong, negative, linear correlation between the average March Temperature and the day in April a cherry blossom blooms"?
400
Conclusion for a 95% Confidence interval of (.1,.3) when the null hypothesis is p = .25
What is "We fail to reject H0. We do not have convincing evidence for Ha"?
400
The standard deviation of the difference between two random variables.
What is the square root of the sum of the variances of the two random variables?
400
The rule for finding the probability of obtaining the first success on the 5th trial if p = .4
What is P(X=5) = .4(1-.4)^4 = .052
or What is geometricpdf(.4,5) = 0.052
400
This procedure is conducted to answer the following: Are younger people more likely to be vegan/vegetarian? To investigate, the Pew Research Center asked a random sample of 1480 US adults for their age and whether or not they were vegan/vegetarian.
What is a "chi square test for independence"?
400
A 95% confidence interval with a random sample of size 40, sample mean of 10 and sample standard deviation of 2.1
What is tInterval(
Sample Mean (x̄) = 10
St Dev (Sx) = 2.1
Sample Size (n) = 40
C-Level = .95
= (9.33, 10.67)
500
A variable that is not part of the study that can affect the explanatory and response variables.
What is a confounding variable?
500
A random sample of teachers were asked to report the age and mileage of their primary vehicle. This linear regression equation represents the predicted amount of miles a car has based on the age of the car.
What is "ŷ = 12188x + 3704"?
500
np = 15; n(1-p) = 9
What is "The Large Counts condition is not met"
500
The expected count for any value in a chi square 2-way test
What is the row total times the column total divided by the grand total?
500
The probability for finding exactly 10 successes in 15 trials if p = .75 (do not use calculator function)
What is
P(X=10) =
(15 Choose 10) * (.75)^10 * (1-.75)^5
= .17
binomialPDF(trials: 15, p=0.75, x=10)
500
How seriously do people view speeding in comparison with other annoying behaviors? A large random sample of adults was asked to rate a number of behaviors on a scale of 1 (no problem at all) to five (very severe problem). Do speeding drivers get a higher average rating than noisy neighbors?
What is a "paired t test for the mean difference"?
500
If more than 50% of the student population supports changing the schedule, lunch will be moved to earlier in the day. The principal took a random sample of 100 students and found the 54 supported the change. Calculate the p-value for this test.
What is 1-PropZTest(
p0 = 0.5
x = 54
n = 100
prop > p0