STAT 1350 Lecture Notes - Lecture 21: Null Hypothesis, Statistic, Statistical Hypothesis Testing
27 Apr 2018
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3/29/2018
Chapter 22: What is a test significance?
● Remember the steps in hypothesis testing
○ 1. Determine the null hypothesis and the alternative hypothesis.
○ 2. Collect data, summarize the data, and convert the sample statistic to a test
statistic (or a z-score).
○ 3. Find the p-value by using Table B.
○ 4. Make a decision based on the p-value by comparing it to the significance level
(or alpha (α)).
● A New Example: Networking
○ It has been claimed that 85% of jobs are filled through networking. You believe
this percentage is too high. You obtain a random sample of 130 employees and
find that 107 obtained their current job through networking. Conduct a
hypothesis test using a = .05.
○ https://www.linkedin.com/pulse/new-survey-reveals-85-all-jobs-filled-via-
networking-lou-adler/
● How Should We Get Started
○ State the hypotheses:
■ Ho:
■ Ha:
○ Once the data has been gathered, think about what the sampling distribution will
look like. What shape will it have? Where will it be centered? What is the
standard deviation?
● Pulling an all-nighter
○ According to medical researchers, 20% of college students pull all-nighters at
least once a month.
○ Believing this number is too low, you survey a random sample of 100 of your
peers, and you find that 26 of them report pulling all-nighters at least once a
month.
○ Conduct a hypothesis test at an alpha-level of 0.10.
● Pulling an all-nighter
Document Summary
Determine the null hypothesis and the alternative hypothesis. Collect data, summarize the data, and convert the sample statistic to a test statistic (or a z-score). Make a decision based on the p-value by comparing it to the significance level (or alpha ( )). It has been claimed that 85% of jobs are filled through networking. You obtain a random sample of 130 employees and find that 107 obtained their current job through networking. Conduct a hypothesis test using a = . 05. Once the data has been gathered, think about what the sampling distribution will look like. According to medical researchers, 20% of college students pull all-nighters at least once a month. Believing this number is too low, you survey a random sample of 100 of your peers, and you find that 26 of them report pulling all-nighters at least once a month. Conduct a hypothesis test at an alpha-level of 0. 10. Calculating the test statistic and finding the p-value.
