A researcher is looking into whether who wear Crocs sandals are
less cool than people who wear other sandals. He knows that the
mean “coolness” score for people who wear other sandals is 21, with
a population standard deviation of 6. He takes a sample of 9 people
who wear Crocs and finds a sample mean coolness score of 17.4.
Should the researcher reject the null hypothesis in this study?
Assume alpha = .05.
a. No, they should not reject...
A psychologist is interested in the effects of animal therapy on
kids who have an anxiety disorder. She knows that the population
mean on a test of anxiety for these kids is 24.7 with a standard
deviation of 3.9. She collects a sample of 27 children and exposes
them to therapy dogs for a period of 6 months. She then tests their
anxiety levels and obtains a mean of 22.3.
A. Test the hypothesis that therapy influences anxiety in
children...
A researcher was interested in whether the female students who
enrolled in her stats course were more interested in the topic than
the males. The researcher obtained a random sample of
8 male and 8 female students and
gathered their scores on an Interest in Statistical Topics (IST)
Survey.
Girls’ IST scores: 21, 37, 22, 20, 22, 20, 22, 21
Boys’ IST scores: 20, 20, 20, 21, 21, 20, 23, 21
Test the researcher’s hypothesis using α =.05
Please show...
Scenario: Imagine you are a researcher who is interested in
studying whether sleep deprivation leads to increased reaction
times (i.e., being slower) when driving. You randomly select a
sample of 30 licensed drivers. Fifteen participants are randomly
assigned to get 5 hours of sleep for three consecutive nights. The
other 15 participants are randomly assigned to get 8 hours of sleep
for three consecutive nights. For the purposes of this Assignment,
assume that all participants sleep exactly the required amounts....
A researcher is interested in examining whether different
practice strategies have an influence on the accuracy of basketball
players' free throws. The researcher collected data from a sample
of 18 participants who were classified in one of three groups: (1)
6 players who received no special practice, (2) 6 players who spent
30 minutes just imagining that they were shooting baskets, and (3)
6 players who spent 30 minutes actually practicing shooting
baskets. After participating in the experiment for two...
1. A
university researcher is
interested in whether
recent recruitment efforts
have changed the
type of students
admitted to the
university. To test
this, she randomly
selects 50 freshmen
from the university
and records their
high school GPA.
The mean is 2.90
with a standard
deviation of 0.70.
The researcher also
knows that the mean
high school GPA of
all freshmen enrolled
at the university
five years ago was
2.75 with a
standard deviation of
0.36. The researcher
wants ...
Pretend you are a researcher interested in evaluating the IQ of
a class of “gifted” fifth-graders to see whether their mean IQ is
significantly higher than the mean IQ of the general population.
You administer a standardized IQ test to the “gifted” fifth-grade
class and the data are provided in “Raw Data.txt”. Assume it is
known that the IQ test you are using has a mean of 100 and a
standard deviation of 15 when given to fifth-graders in general....
A researcher is interested in whether or not there is a
difference in student’s performance based on the study methods they
use. Participants are assigned one of three different study methods
(read the text and re-read it, read and answer prepared questions,
and read then create your own questions). There are 6 people in
each group and the researcher measures the participants’
performance on a test. Perform a hypothesis test and show all four
steps. Hints: Use a two tailed...
A researcher would like to test whether or not people who have
stocked up on a year’s supply of toilet paper are experiencing less
stress during a statewide stay-at-home order. A statewide poll
indicates that the average stress level for the general state
population is 60.5 (with a standard deviation of 11.6) and is
normally distributed. Using a random sample of 36 toilet paper
hoarders that have a mean stress level of 54.7 (and a standard
deviation of 10.3), test...
A family researcher is interested whether there is an
association between the number of siblings a person has and the
number of children they have. She interviews six older adults and
finds the following information.
Number of Siblings
Number of Children
0
1
1
1
2
1
2
0
3
3
4
3
Mean Number of Siblings = 2
Mean Number of Children = 1.5
Standard Deviation = 2
Standard Deviation = 1.5
Explain which variable more naturally plays the...