CFU: null hypothesis and p-values

The hypothesis that two groups are the same.

• Alternative hypothesis

• Experimental hypothesis

• Null hypothesis

• Statistical hypothesis

Which of the following is NOT a null hypothesis?

• Cats are no smarter than dogs

• Americans enjoy hot dogs twice as much as hamburgers

• There is no difference in test scores of students who drink coffee and those that don't

• Students spend as much time on TikTok as on Instagram

The threshold for "significance" in biology is usually alpha = 0.05. What can you conclude if the p-value is < 0.05?

• Reject the null hypothesis - the two groups are statistically significantly different

• Reject the null hypothesis - the two groups are NOT statistically significantly different

• Fail to reject the null hypothesis - the two groups are statistically significantly different

• Fail to reject the null hypothesis - the two groups are NOT statistically significantly different

p = 0.83

• Reject the null hypothesis

• Fail to reject the null hypothesis

p = 0.47

• Reject the null hypothesis

• Fail to reject the null hypothesis

p = 0.0203

• Reject the null hypothesis

• Fail to reject the null hypothesis

p = 0.01

• The two groups are statistically significantly different

• The two groups are NOT statistically significantly different

How likely it is to get a result like the observed result if the null hypothesis is true.

• Alternative hypothesis

• Chi-squared value

• Critical value

• p-value