Hypothesis Test of Means Flashcards
What is the aim of hypothesis testing ?
Aim of hypothesis testing is to decide if sample results are consistent with some assumption made about the population
Describe the purpose of a T-test:
To test whether the population mean of an interval scale variable is equal to a certain value.
What do you look for in SPSS results when doing a paired sample T test?
Two-sided p value
Greater or less than 0.05
When do you use a paired sample t test ?
If the 2 groups are paired
When do you use an independent sample t-test ?
When the population means are from two independent groups an independent samples t-test is used
How do you conduct a paired sample t-test in SPSS?
Analyze > Compare Means > One-Sample T Test
How do you conduct an independent sample t test on SPSS ?
Analyse>Compare Means> Independent-samples t test
How do you obtain the p value ?
To obtain a P-value, the test statistic is then compared against the t-distribution with (n1 + n2 – 2) degrees of freedom if the sample sizes are small or the N(0,1) distribution if sample sizes are large.
What are the 2 assumptions made when doing an independent sample t-test ?
The standard deviation in the two populations should be similar
When the size of either of the two random samples is small (i.e. n1<30 or n2<30), the variable of interest should be Normally distributed in the population from which the first sample came and in the population from which the second sample came
Do you reject or not reject null if p-value is below significance level?
If p-value is less than significance level of 0.05 reject null
What is the usage of carrying out an independent samples t-test ?
To test whether the mean of an interval scale variable in one group is equal to the mean in another group when the two groups are independent
What is the usage of a paired samples t-test ?
To test whether the mean of an interval scale variable in one group is equal to the mean of an interval scale variable in another group when there exists a pairing between group
