Lecture 2 - Inferential Stats/Confidence Intervals

Question 1

is the distribution of larger sample means narrower or wider than the distribution of smaller samples?

Answer 1

narrower (ie closer to actual mean)

Question 2

equation for standard error

Answer 2

SD/(square root n)

n = sample size
SD = standard deviation

Question 3

as you increase the sample size, the standard error _____

Answer 3

decreases

Question 4

____ % of the data lies within +/- 1 standard deviation;
____ % of the data lies within +/- 2 SDs.
____ % of the data lies within +/- 3 SDs

Answer 4

68;
95;
99.7

Question 5

an increase in the size of n results in a more (accurate or precise) determination

Answer 5

precise

Question 6

to decrease a standard error of means by half, you would need to increase the n of the sample by ___

Answer 6

4x

Question 7

Z score vs T-statistics:
_____ is the distance from the means in terms of the SD of the population. _____ used sample-based standard error of means

Answer 7

Z-score;

T-stats

Question 8

equation for Z score

Answer 8

Z = (X - mean) / SD

X = data point

Question 9

equation for T score:

Answer 9

t = (X - u) / Standard Error

u = mean of sample

Question 10

variance is based on the _____ of the _____ of the deviation scores

Answer 10

mean, square