1. A hypothesis is a guess about a population statistic, such a mean.
a. If technological improvement increases productivity, then the mean
of growth will be greater than 0.
2. We start by asking what
1. Probability sample: every response ahs an equal chance of being randomly selected. a. Keep doing random sample we get a different number but similar. 2. Sample mean is a random variable. This signi
1. Standard Normal Distribution: Is symmetric has half on each side of mean.
a. We will compare our data distribution to the Normal Distribution.
2. Skewed distribution will have a lot of observations
1. Describing varations
a. Interquartile range: is the distance between the 25 th to 75th percentile.
The smaller distance means more people fall around the mean/median. 2. Box Plot
a. Shows the 25th,
1. Proportion of people who agree is people who agree over the total number
of respondents. The percent is the proportion multiplied by 100.
2. Are there systematic differences between two groups
a. T
a. Stratified random sample
i. Break into groups do probability sampling within groups.
ii. At the end proportion of each group matches population
proportion. Overrepresent in the sample that control
1. Good sample have characteristics a. Representative of the underlying population. Looks like population. Don't only want to look at males or females and apply it to everyone.
b. Large enough to draw
a. Running records: i. have lower costs ii. More superficial iii. May be systematically altered iv. Increased sample size v. Government data can sometimes be of poor quality.
2. Challenge of Sampling:
1. Factors in deciding type of observation
a. Cost: cheaper is better. Some techniques are cheaper than others.
b. Availability: are you going to be able to gain access to the
individuals you want to
1. Primary v. Secondary
a. Primary data is data that the researcher themselves create.
i. Creating a transcript from an interview. Results from an
experiment you created.
ii. Primary because you are t
1. Segal and Cover: measure ideology of SCOTUS justices a. Looked through newspaper editorials written about each justice. Based on these editorials, can figure out how liberal or conservatives. b. Lo