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- Statistics & Probability
- Any idea about our lesson for today?
- It is a random variable that is calculated from sample data and used in hypothesis test.
- LESSON: Test Statistics
- Test statistics has two different types, it is the z-test and the t-test.
- Statistics & Probability
- We can only use the z-test when our sample size must be greater than or equal to 30. (n > 30) In addition, its z-score value is calculated with population parameters. Any another ideas?
- When should we use the z-test?
- I think that z-test follows a normal distribution.
- It is also used when the population standard deviation is known.
- Statistics & Probability
- In this test the population variance or the population standard deviation is unknown.
- When should we use the t-test?
- based on our book, it says that the sample size in the t-test must be less than 30 ( n < 30 )
- How about its sample size? Is it the same in the z-test?
- Statistics & Probability
- and lastly for our lesson for today, let me explain to you the central limit theorem.Central limit theorem is used when the sample size is extremely large and when the population variance is unknown.
- Central Limit Theorem
- ooh so it is just the same in the z-test? but the only difference is the population variance is unknown? Am i right Denise?
- Yes
- Statistics & Probability
- An agent believes that the average closing cost of purchasing a new home is ₱328,250. She selects 40 new home sales at random and finds that the average closing cost is ₱333,300. The standard deviation of the population is ₱6,060. What is the test statistic appropriate to used?
- For your activity, I need you to identify which test statistic is appropriate in this given problem.
- Yes Sir
- okay Sir, thank you.
- Statistics & Probability
- An agent believes that the average closing cost of purchasing a new home is ₱328,250. She selects 40 new home sales at random and finds that the average closing cost is ₱333,300. The standard deviation of the population is ₱6,060. What is the test statistic appropriate to used?
- I also think that z-test would be the appropriate test statistic in this problem.
- I think that we should use the z-test because the population standard deviation is known and its sample size is greater than 30. How about you? what do you think?
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