Question

in the population, the average IQ is 100. A team of
researchers wants to test a new coaching method to see if it has
any effect at all on students. a sample of 30 participants who were
coached have a mean IQ score of 140 with a standard deviation of
20. did coaching affected intelligence?

define null hypothesis, state the alpha level, state decision rule,
calculate the test statistic, state result, state conclusion

Answer #1

IQ: Scores on a certain IQ test are known to have a mean of 100
. A random sample of 51 students attend a series of coaching
classes before taking the test. Let μ be the population mean IQ
score that would occur if every student took the coaching classes.
The classes are successful if μ > 100 . A test is made of the
hypotheses
H0 :μ=100 versus H1 :μ>100. Consider three possible conclusions:
(i) The classes are successful....

You wish to test the
claim that the average IQ score is less than 100 at the .005
significance level. You determine the hypotheses are:
Ho: μ=100
H1:μ<100
You take a simple
random sample of 76 individuals and find the mean IQ score is 95.5,
with a standard deviation of 15.1. Let's consider testing this
hypothesis two ways: once with assuming the population standard
deviation is not known and once with assuming that it is known.
Round to three decimal...

You wish to test the claim that the average IQ score is less
than 100 at the .01 significance level. You determine the
hypotheses are: H o : μ = 100 H 1 : μ < 100 You take a simple
random sample of 60 individuals and find the mean IQ score is 98.7,
with a standard deviation of 14.6. Let's consider testing this
hypothesis two ways: once with assuming the population standard
deviation is not known and once with...

You wish to test the claim that the average IQ score is less
than 100 at the .005 significance level. You determine the
hypotheses are: H o : μ = 100 H 1 : μ < 100 You take a simple
random sample of 95 individuals and find the mean IQ score is 95.2,
with a standard deviation of 14.4. Let's consider testing this
hypothesis two ways: once with assuming the population standard
deviation is not known and once with...

The Stanford-Binet IQ test has scores that are normally
distributed with a mean of 100. A principal in an elementary school
believes that her students have above average intelligence and
wants verification of her belief. She randomly selects 20 students
and checks the student files. She finds the following IQ scores for
these 20 students. IQ scores: 110,132, 98, 97, 115, 145, 77, 130,
114, 128, 89, 101, 92, 85, 112, 79, 139, 102, 103, 89
a. Compute the sample...

A professor at a small college suspects that poor readers may
test lower in IQ than those whose reading is “satisfactory.”
(Possibly AT grade level?) She draws a random sample of 28 students
who are labeled as “poor readers.” She examines the data in the
historical archives and finds a population mean IQ of 105. The
sample of 28 has a mean of 103.8 with a sample standard deviation
of 1.42. Again using a level of significance of 0.05, test...

In the population, IQ scores are normally distributed with a
mean of 100. A charter school wants to know if their students have
an IQ that is higher than the population mean. They take a random
sample of 15 students and find that they have a mean IQ of 109 with
a sample standard deviation of 20. Test at 1% significance level
whether the average IQ score in this school is higher than the
population mean.
a) Write down null...

You wish to test the claim that the average IQ score is less
than 100 at the .05 significance level. You determine the
hypotheses are: H o : μ = 100 H 1 : μ < 100 You take a simple
random sample of 38 individuals and find the mean IQ score is 98.8,
with a standard deviation of 15.9. Let's consider testing this
hypothesis two ways: once with assuming the population standard
deviation is not known and once with...

The mean IQ score of humans is 100. Suppose a student at Suffolk
University wonders if college students have higher-than-average IQ.
He obtains a simple random sample of 40 college students and finds
the mean IQ is 104.7 with a standard deviation of 12.5. Conduct a
hypothesis test at 10% level of significance to see whether there
is strong evidence to support the student’s claim.
a. State the null and alternative hypotheses. Specify the type
of test.
b.Compute the test...

For the general population, IQ test scores are normally
distributed with a mean of 100 and a variance of 225.
The IQ scores for a sample of 81 randomly selected chemical
engineers resulted in a variance of 144.
We want to test the claim that the variance for chemical
engineers is less than that of the general population.
1. What is the Null Hypothesis and the Alternative
Hypothesis?
2. If we use a 0.01 significance level, what is the critical...

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