Question

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. (ii) The classes are not
successful. (iii) The classes might not be successful.

Part 1 of 2

Which of the three conclusions is best if H0 is not rejected? The best conclusion is (Choose one) ▼ .

Part 2 of 2

Assume that the classes are not successful. Is it possible to make a Type II error? Explain.

(Choose one) ▼ , a type II error (Choose one) ▼ possible. The classes are not successful when the null hypothesis is (Choose one) ▼ .

Answer #1

IQ scores among the general population have a mean of
100
and a standard deviation of
15
. A researcher claims that the standard deviation,
σ
, of IQ scores for males is less than
15
. A random sample of
16
IQ scores for males had a mean of
98
and a standard deviation of
10
. Assuming that IQ scores for males are approximately normally
distributed, is there significant evidence (at the
0.1
level of significance) to conclude...

A test is made of H0: μ = 25 versus H1: μ ≠ 25. The true value
of μ is 28 and H0 is rejected. Determine whether the outcome is a
Type I error, a Type II error, or a correct decision.
a-Correct decision
b-Type II error
c-Type I error

A certain IQ test is known to have a population mean of 100 and
standard deviation of 15 in the general population. You want to
test whether psychology majors have a different average IQ than the
population as a whole. Assume the variance of IQ is the same for
Psych majors as it is in the general population.
Suppose that Psychology majors actually have an average IQ of
108. If you do a 2-tailed test at α= .05 with a...

IQ scores follow a
Normal distribution with a mean μ = 100 and standard
deviation σ = 15. A SRS of 31 seventh-grade girls in one
school district is tested and the sample mean x¯¯¯x¯ was =
102 . Is there evidence that the mean IQ score in this district is
different from from 100?
The alternative
hypothesis is:
Ha: u < 100
Ha: u > 100
Ha: u ≠ 100
The test statistic, z
=....... (+ 0.01)
P(z )...

Determine whether the outcome is a Type I error, a Type II
error, or a correct decision.
A test is made of H0: μ = 25 versus H1: μ ≠ 25. The true value
of μ is 25 and H0 is rejected.

Question1: It is known the population IQ score follows a normal
distribution with mean as 100, SD as 10. A researcher is interested
in studying if the average IQ of students from statistics courses
on average has a higher IQ score than the population IQ score. To
test this hypothesis, the researcher randomly collected a sample of
25 students from statistic class, the mean IQ score for this sample
is 110. Compete for the hypothesis test at significant level.
Step...

Scores of an IQ test have a bell-shaped distribution with a mean
of 100 and a standard deviation of 14. Use the empirical rule to
determine the following.
A.) What percentage of people has an IQ score between 86 and
114?
B,) What percentage of people has an IQ score less than 72 or
greater than 128?
C.) What percentage of people has an IQ score greater than
142?
A.) ____% (Type an integer or a decimal).
B.) ____ %...

Type I error: Washers used in a certain
application are supposed to have a thickness of 2 millimeters. A
quality control engineer measures the thicknesses for a sample of
washers and tests H0: μ = 2 versus
H1: μ ≠ 2.
b. If a Type II error is made, what conclusion will be drawn
regarding the mean washer thickness?

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...

Scores of an IQ test have a bell-shapped distribution
with a mean of 100 and standard deviation of 15. Use the empirical
rule to determine the following.
A.) What percentage of people has an IQ between 55 and
145?
B.) What percentage of people has an IQ score less than
85 or greater than 115?
C.) What percentage of people has an IQ score greater
than 145?
(Type an integer or decimal.)

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