Prelab 7 Statistics

Mean

Shows central tendency of data, average

Standard Deviation

Shows how scattered the data are around the mean, larger the SD the more spread

Standard Error

Estimate of the standard deviation of a sample, used to analyze sample data

Histogram

Shows distribution of one variable, used to see data spread and shape

Bar graph

Compares means of 2+ groups, includes error bars (standard error)

Scatter plot

Shows relationship between two variables, independent/dependent variable

t-Test

Used to compare two averages

Null hypothesis

Assumes no difference between groups

Student’s t (Test Statistic)

Measure how large the difference between groups is

P-value

Probability that the difference occurred by chance

p<0.05

statistically significant

p>0.05

not statistically significant

p<0.05

reject null hypothesis

p>0.05

fail to reject null hypothesis

Linear regression

y=ax+by, relationship between two variables

R-squared

Shows how well linear regression fits the data, closer to 1 = closer relationship, closer to 0 = weaker relationship

p-value tells…

probability that the result happened by chance