Formulas
What formula is this for?
? = P(A)+P(B)-P(A n B)
P(A u B)
What type of experiment is this?
Randomly select 30 subjects from the population. Randomly select 15 and assign them to treatment A, then assign the remaining 15 to treatment B.
simple random sample
conclude a p-value of 0.92 with an alpha of 0.05.
since the p-value of 0.92 is greater than alpha=0.05, fail to reject Ho. we do not have convincing evidence to suggest (context).
what inference procedure should you run?
phat=.15
n=30
one sample z test for p.
what is phat?
sample proportion
What formula is this for?
1/p = ?
Mx for a geometric distribution
what are 2 events that cannot occur at the same time called?
mutually exclusive
interpret a mean of 10 red m&m in a sample of 30 m&ms.
if many, many samples of 30 m&ms are taken the average number of red m&ms is about 10 (context).
what procedure should you run?
n1=30 n2=30
M1=15 M2=12
stdev1=2 stdev2=4
two sample t test for M
what is SD?
standard deviation
What formula is this for?
? = (X1+X2)/(n1+n2)
pc - hat
what allows you to generalize to the population?
random selection
interpret a z-score of -1.67. for a quiz score of 71.
a quiz score of 71 is 1.67 below the mean.
100 students SAT scores were before and after taking a prep class. what procedure should you run to see if there is evidence to suggest that the mean SAT score increases after taking a prep course.
one sample matched pairs test Md
what is xbar?
sample mean
What formula is this for?
? = E(observed-expected)2/expected
x2 statistic
what allows you to determine causation?
random assignment
interpret the confidence level of 95% for the population mean number of students who buy lunch.
if we take many, many samples of the same size and calculate a confidence interval for each, about 95% of them will capture the true population mean number of students who buy lunch.
on average how many days do students skip school as the number of schools days increases? what procedure should you run?
linear regression t test for B
what is B?
beta
What formula is this for?
? = square root of (E(yi-y(hat)i))2/(n-2)
standard deviation of b
what is the term for the probability of correctly rejecting a false null hypothesis?
power
interpret a slope of 1.2 that describes the relationship between the number of tardies and the number of times they get dunkin before school
with each additional Dunkin visit before school the predicted number of tardies increases by 1.2.
determine if there is an association between what sport you play and hours of homework. what procedure should you run?
chi-squared test for association
what is N?
population size