Question

- When we carry out a 1-sample hypothesis test for the mean, one of the ways that we can check for normality is to look at the normal plot. How do we know if our normality assumption is satisfied by looking at the normal plot?

Answer #1

Suppose that we want to test the null hypothesis that the mean
of population 1 is equal to the mean of population 2. We select a
random sample from population 1 and a random sample from population
2, and these two samples are independent. Circle the FALSE
statement.
A. We need to perform a two-sided test.
B. If we know the variance of each population, even if they are
different, we can use the Z test. That is, the test...

1. Why do we say that we "fail to reject" the null instead of
saying "accept"?
2. When selecting a significance level, why should we consider
the consequences of a type 1 error?
3. Based on the QQ plot, does the variable age pass the
normality assumption?
4. If we set our alpha at 0.05, that means
a) we have a 5% chance of making a type 1 error b)we have a 5%
chance of being correct c) 5% of...

The code presented below will allow to carry out a test of the
null hypothesis. The first line reads in the observed frequencies
(based on our sample) for each phenotype. The second and third
lines allow us to obtain the expected frequencies given the
hypothesized distribution. Lines 4 and 5 simply display the
observed and expected frequencies. The 6th line contains the
hypothesized distribution (this is what we believe it to be). The
last line provides the statistical test that...

We have a left tail one sample test for the population mean.
Assume the null hypothesis is true. Use 4% for the significance
level. The sample size is 27, the sample mean is 32.8, the sample
standard deviation is 4.1, and the null mean is 35.
The test result is (a) a correct decision (b) a Type I error (c)
a Type II error 3.
The test statistic value for the previous problem is

For each of the following data sets, carry out a one-tailed
t-test, with α = 0.05, and the alternative hypothesis ????????: U1
> U2
In each case, give the p-value (if applicable) or explain why
the data are inconsistent with the alternative hypothesis. State
whether or not the null hypothesis is rejected.
a) Sample 1: n=10 , mean= 10.8
Sample 2: n= 10, mean= 10.5 df= 18 SE= 0.23
b) Sample 1: n= 100, mean 750
Sample 2: n=100, mean=...

Which hypothesis test do we use when comparing more than two
samples of normal data?
Select one:
a. 1 sample t test
b. HOV
c. Regression
d. ANOVA

1)When a truckload of apples arrives at a packing plant, a
random sample of 225 is selected and examined for bruises,
discoloration, and other defects. The whole truckload will be
rejected if more than 10% of the sample is unsatisfactory. Suppose
that in fact 12% of the apples on the truck do not meet the desired
standard. What’s the probability that the shipment will be accepted
anyway? Give your answer to 4 decimal places.
2-1) In 1960, census results indicated...

Hypothesis Test for 1 -Proportion Z
2) of children are believed to carry a gene that predisposes
them to juvenile diabetes. Researchers find in a sample of 732
newborns 87 carry the gene.
a) What is the sample proportion p^. What is u p^ and s p^
b) Given the claim that 10% of children have this gene, test at
the .05 significance level that the true proportion is greater than
.10
Description
Hypotheses:
Conditions check: the Normal Distribution is...

When we conduct a hypothesis test, there are two ways to make a
mistake. The null hypothesis might be correct, and we end up
rejecting it. This is called a Type I error. On the other hand, the
null hypothesis might be false, and we fail to reject it. This is
called a Type II error. Either type of error can be costly, though
not necessarily equally costly. In the following two scenarios,
think about what is the alternative hypothesis?...

1. To give you guided practice in carrying out a hypothesis test
about a population proportion. (Note: This hypothesis test is also
called a z-test for the population proportion.)
2. To learn how to use statistical software to help you carry
out the test.
Background: This activity is based on the
results of a recent study on the safety of airplane drinking water
that was conducted by the U.S. Environmental Protection Agency
(EPA). A study found that out of a...

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