Statistics Significant Test

Which of the following best describes a Type I error?

• The null is true, but we mistakenly reject it.

• The null is false and we reject it.

• The null is false, but we fail to reject it.

• The null is true but we fail to reject it.

• The null is true, and we fail to reject it.

To test a claim about a mean, when the population standard deviation is unknown we use:

• z procedures

• Pythagorean Theorem

• t procedures

• np > 10 and n(1-p) > 10

What does it mean when a test is statistically significant?

• it has reached alpha level status

• the test statistic had a P-value higher than the alpha level

• the test statistic had a P-value lower than the alpha level

• it is important in practical terms

When conducting a significance test for the difference in proportions, why do we pool the data when finding standard error?

• Because we like to swim

• Because we assume p1 = p2 in Ho

• Because the sample sizes are always equal

• To be safe and make sure we don't underestimate the standard error

• Because we don't the standard deviation.

When p-value is greater than alpha we:

• Accept Ho

• Accept Ha

• Fail to reject Ho

• Reject Ho

Which of the following best describes a type II error?

• The null is true, but we mistakenly reject it.

• The null is false and we reject it.

• The null is false, but we fail to reject it.

• The null is true but we fail to reject it.

• Te null is false, and we reject it.

A random sample of 49 medical doctors in LA showed that they worked an average of 53.1 hours/week with a standard deviation of 7.2 hours/week. If the California average is 60 hours/week, does this give evidence that the LA doctors work significantly less than the rest of California?

• One-Sample T Test for a Mean

• One-Sample Z Test for a Mean

• One-Sample T Test for a Proportion 

• One-Sample Z Test for a Proportion

White blood cell counts are normally distributed with mean 7500 and variance 500. If a patient has taken 50 laboratory blood tests that have a mean of 6899.75 and a standard deviation of 393.44, does this give evidence that his white blood cell count is significantly different than normal?

• One-Sample T Test for a Mean

• One-Sample Z Test for a Proportion

• One-Sample Z Test for a Mean

• One-Sample T Test for a Proportion

USA Today reported that in 1992, 39% of all elementary school children claimed that when they grow up they want to do something to help other people. However, in 1995, 128 of a random sample of 317 of these same children claimed that when they grow up they want to do something to help other people. Does this information indicate that there has been an attitude change either way?

• One-Sample Z Test for a Proportion

• Two-Sample Z Test for the Difference in Proportions

• One-Sample T Test for a Mean

• Two-Sample T Test for the Difference in Means

The manager of a sporting goods store offered a bonus commission to his salespeople when they sold more goods. A new manager dropped the bonus system. For a random sample of six sales people, the weekly sales (in thousands of dollars) are shown in the following table with and without the bonus system
Salesperson   1 2 3 4 5 6
with bonus 2.9 3.0 5.8 4.4 5.3 5.6
w/o bonus 2.8 2.5 5.9 3.5 4.6 4.6
difference 0.1 0.5 -0.1 0.9 0.7 1.0

• Matched-Pairs T Test for a Mean

• One-Sample T Test for a Mean

• Two-Sample T Test for the Difference in Means