STS 110 Lecture Notes - Lecture 22: Null Hypothesis, Statistical Hypothesis Testing, Alternative Hypothesis
27 Apr 2018
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STS 110!
Hypothesis Testing !
Understand: !
1) Definition and examples of hypothesis testing !
2) Null and alternative hypothesis !
3) Independent v.s. dependent samples!
1- Hypothesis testing!
Definition: Two conflicting statements are made about two population means. Data is collected
and analyzed to determine which statement is more likely to be correct. This is called a
hypothesis test !
Examples: !
1) A sociologist believes freshman sleep the same number of hours on the weekend as
seniors. A doctor believes freshman sleep less than seniors on the weekend.!
2) The mean score on sporcle on attempt one is equal to the mean score on sporcle on
attempt two or the mean score on sporcle on attempt one is less than the mean score on
attempt two.!
3) A scientist believes that the mean height of daughters equals the mean height of their
biological mothers. A doctor feels that the mean heights are different.!
2- Null and alternative hypothesis !
-Null hypothesis —> states the two means are equal !
-Denoted by H(sub 0)!
-Alternative hypothesis —> states that one mean is less than the other, greater than the other,
or different than the other !
-Denoted by H(sub 1/a) !
Writing the null and alternative hypotheses in symbols !
1 ) Hsub0: M1 = M2!
Hsub1: M1 > M2!
2) Hsub0: M1 = M2!
Hsub1: M1 < M2!
3) Hsub0: M1 = M2!
Hsub1: M1 does not equal M2!
Hsub0: null hypothesis!
Hsub1: alternative hypothesis !
Mu: population mean!
Mu1: population mean for group 1!
Mu2: population mean for group 2!
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Understand: de nition and examples of hypothesis testing, null and alternative hypothesis. De nition: two con icting statements are made about two population means. Data is collected and analyzed to determine which statement is more likely to be correct. Examples: a sociologist believes freshman sleep the same number of hours on the weekend as seniors. A doctor feels that the mean heights are di erent. Null hypothesis > states the two means are equal. Alternative hypothesis > states that one mean is less than the other, greater than the other, or di erent than the other. Writing the null and alternative hypotheses in symbols. Hsub1: m1 > m2: hsub0: m1 = m2. Hsub1: m1 < m2: hsub0: m1 = m2. Mu2: population mean for group 2: ex1, hsub0: mfreshman = mseniors, hsub1: mfreshman < mseniors, ex2, hsub0: mattempt1 = mattempt2, hsub1: mattempt1 < mattempt2, ex3, hsub0: mdaughtersheight= mmothersheight, hsub1: mdaughtersheight does not equal mmothersheight.
