Sampling & Experiments
Neither the subject nor those who measure the reponse variable know which treatment a subject received.
What is a double-blind experiment?
P-value = 0.03, alpha = .05
What is "we reject the null hypothesis, and have enough evidence to support the alternative hypothesis"?
How to algebraicly identify outliers
What is Q1 - 1.5(IQR) and Q3 + 1.5(IQR)?
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?
N(12,3); P(X < 8) (any method)
What is normcdf(-9999, 8, 12, 3) = .091?
A Coke vs. Pepsi taste test is a common form of this experimental design
What is matched pairs?
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"?
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?"
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?
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?
When some groups in the population are left out of the process of choosing a sample
What is undercoverage?
A z-score of -3.45
What is "The data value is 3.45 standard deviations below the mean"?
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)?
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
The z* for a 92% confidence interval
What is invNorm(.04) = -1.75 = 1.75?
The population is divided into groups. Some groups are randomly selected and all individuals in the chosen groups are sampled.
What is cluster sampling?
95% Confidence interval is (.1,.3) and null hypothesis is p = .25
What is "We fail to reject H0. We do not have enough evidence for Ha"?
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?
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
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(10, 2.1, 40, .95) = (9.33, 10.67)?
A variable that is not part of the study that can affect the explanatory and response variables.
What is a confounding variable?
np = 15; n(1-p) = 9
What is "The Large Counts condition is not met"
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?
The probability for finding exactly 10 successes in 15 trials if p = .75 (do not use calculator function)
What is P(X=10) = (15 C 10)*.75^10*(1-.75)^5 = .17?
Three random integers from 1 to 100.
What is RantInt(1,100,3)