Statistical Inference

Between a Population and Sample: which size is bigger ?

• Population

• Sample

• Both can be the same

• Not enough information

If you are given the population standard deviation, what should be the minimum size of the sample?

• 30

• 30 or more

• it doesn't matter

• not enough information

Depending on the information given, select the cases where you won't be able to calculate the interval of the population mean

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What is the lowest recommended confidence interval one should use to predict the population mean?

• 90%

• 95%

• 50%

• any percentage is fine

If looking for 0.0077 in the table, which value of z should you use?

• -2.43

• -2.42

• -2.425

• not enough information

If looking for 0.0324 in the table, which value of z should you use?

• -1.84

• -1.85

• -1.845

• not enough information

What´s the margin of error?

• not enough information

What data relates to the given problem?

We measure the heights of 40 randomly chosen men and got a mean height of 175cm. The population variance is 25 cm. With a 99% confidence level, determine the average height of all men.

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If using a 95% confidence level, what value of z should you use?

Which symbol represents the mean of a sample?