Term 2 Week 2 single sample T-test

Question 1

The One Sample t Test compares a sample mean to a hypothesized population mean to test

Answer 1

whether the two means statistically significantly differ

Question 2

The One Sample t Test can only compare a single sample mean to a sc. It can not compare sample means between two or more group

Answer 2

specified constant

Question 3

what what is the p value? (IMPORTANT)

Answer 3

probabiltiy of obtaiing the observed t statistic or a more extreme value if the null hypothesis is true

to obtaion p value for a 1 tailed 1/2 the 2 tailed valies given by SPSS output

0.17/2=0.0085 p,0.05 therefore sig different

Question 4

assumptions of a t test (3)

Answer 4

random sample or random allocation to experimental groups

all obs are independent of each other

parametric tests also assume shape of the sampling distribution of mean to be normal

Question 5

what’s the difference between a z and a t test?

Answer 5

Z when the standard deviation of the popualtion sampling from is know

T = when the stantated deviation of the popualtion is an estimate
SD of popautlion is unknown

Question 6

how do you report a t-test in SPSS

Answer 6

t(df) = t, p

Question 7

What are degrees of freedom?

Answer 7

number of data points that are free to vary in any calculation

n general, can be defined as the total number of observations minus the number of independent constraints imposed on the observations

with states tables must use t test distribution appropite for dfs - spss calcuates this automaticall

df=n-1