|
AP Statistics Test Errors and Hypothesis
Testing
- For a two tailed test with a p=.02, What is the area
under the curve associated with p in one of the tails?
Area = 0.01
- If a confidence interval is tripled, what is the effect
on the margin of error? tripled
- If the sample size is increased by a factor of 16, what
is the effect on the margin of error? 1/4 times
original ME
- If the confidence level is changed from 90% to 95% what
is the effect on the margin of error? (1.96 /
1.64) times ME or a 19% increase in ME
- What conditions must be met in order to use a t-test?
SRS, population approximately normally
distributed
- For a given test of statistical significance alpha =
.02 and the p-value = .025. What can you conclude?
There is not a statistically significant reason to
reject the null hypothesis
- Juan obtains a p-value = .018 in his significance test.
How should he interpret it? There is an 1.8%
probability of getting a value of the test statistic as extreme or more
extreme than the one obtained.
- A two tailed quality assurance test has an alpha = 5%.
What is the probability of a type I error?
5%
- Which hypothesis is assumed to be true when evaluating
the probability of a type I error? the null
hypothesis
- What is the sum of the probability of a type I and type
II error for a given set of circumstances?
Unknown
- What is the sum of the probability of a type II error
and power for a given set of circumstances? 1.00
- When is a pooled t-test used?
When the standard deviations of the 2
samples are considered to be equal
- In the American justice system, the presumption of
innocence until proven guilty can be called the _________________.
null hypothesis
- For a hypothesis test beta = 10%. What is the power of
the test? 90%
- Martha plans a survey and wants a margin of error of 2%
with a confidence level of 95%. What is the minimum sample size she should
use? n = 2401
- Based on a survey of 1600 people, Bob finds that 60%
will vote for the purple party. Construct a 95% confidence interval for
the data.
CI = 0.6 ± 1.96 [ .6 (1-.6))/
1600]^0.5 or .6 ± 0.24
- Based on sample of 1000, SC voters vote purple 45% of
the time while based on a sample of 1200 voters, GA voters vote purple 49%
of the time. Construct a 90% confidence interval for the difference
between the two groups. (- 0.075
to -0.0049)
- A sample of Martha's coconuts has an average weight of
1.3 lb with a sample size = 12 and s = 4. A sample of Bob's coconuts has
an average weight of 1.5 lb with a sample size = 10 and s = 3. Are Bob's
coconuts bigger than Martha's? p
= 44.7%
- Create a 80% confidence interval for the difference
between Bob's and Martha's coconuts. (-2.18 to
1.78)
- What does the central limit theorem tell us about the
effects of sample size on the sampling distribution?
As sample size increases, the sampling distribution
narrows and looks more like a normal distribution
- What 2 conditions must be true to use the normal
approximation of the binomial? np
>= 10, n(1-p) >= 10
|