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1. If the alpha level is changed from a- 0.05 to -0.01,
a) What happens to the boundaries for the critical region? (2
pts)
b) What happens to the probability of Type error? (2 pts)
2) researcher investigating the effectiv enes of a new study-
skills training program for elementary school children. sample
of
n= 25 third-grade children selected participate in the program
and each child given standardized chievement test the end of
the year. For the regular population of third-grade children, scores
on the test form normal distribution with mean 150 and a
standard deviation of The mean for the sample is X=1 158.
a) Identify the independent and the dependent variables for this
study pts)
b) Assuming two-tailed test. state the null hypothesi in a
sentence that includes the independent variable and the
dependent variable. pts)
c) Using symbols state the hypothesis (H. and H1) for the two-
tailed test. pts)
d) Sketch the appropriate distribution, and locate the critical
region for 1=0.05. (2 pts)
e) Calculate the test statistic z-score) for the sample. (5 pts)
f) What decision should be made about the null hypothesis and
what decision should be made about the effect of the program
3) Find the values that form the boundaries the critical region
for: two-tailed test with 0.05 for each of the following df values.
a) df= pts)
b)df- pts)
c)
4) sample selected from a
population treatment administered
to sample. treatment, the sample mean
is
found
a) the 10 are the data
sufficient
that
the
treatment
has
signficiant
effect
suing
Df=n-1
5) An elementary school principal would like to know how many
hours the students watching TV each day. sample n-25
children and survey child's parents. The
results indicate hours per day with a
standard
a) Make an interval estimate of the mean so that you are 90%
confident mean in your interval (10 pts)
90%Clofp=x+1.64(ovn)
3.1-1.640F1.46(0.6)=0.876
3.1 .74(0.6)-2.8
90% Clofu:(0.876,28
Complete the following for each problem below (this should all be
calculated by hand. show work to receive full credit):
a) State the null and alternative hypotheses pts)
Ho= Ha#
b) Choose the appropriate statistical procedure (independent or
paired t-test) (2 pt)
c) Identify levelo significance and corresponding critical
value( pts) 0
d) Calculate pts)
e) Express your results in terms of -values(p a)(1 pt)
f) Determine whether your results are significant 2 pt)
g) State in one or two sentences your conclusions pts)
6) Cholesterol measurements from 54 vegetarians and 51
nonvegetarians vield the following data:
Vegetarian 11
12 12
Nonvegetar
Do vegetarians have lower cholesterol levels than nonvegetarians?
Let a = . 01.
Vegitarians mean- 163.33
Nonvegetarian mean 179.90
Difference 16.57
Sd vegitarians=25 .07
Sd nonveg-33.87
= (J((25. 07) /54)+(33. 872/51))=5.84
Z score a=.01 =2.32
5.84x2.32= 13.55
Thereisless than s 1% probability that mean of vegetarian's
cholesterol minus the mean of nonvegetarian cholesterol will be
greater
than
13.55.
Since this sample the difference was 16.571 was greater than
13.55 therefore the results are significant and show vegetarians
have lower cholesterol than nonvegetarians.
7) As part to the effects of certain oral
ontraceptive 12 healthy females were weighed at
the beginning contraceptive usage. They were
reweighed after months. Do the results suggest evidence of weight
gain?
Subject
Initial
IMonth
Weight (lb)
143
140
162
145
150
130
132
Part SPSS Practice
biologist visited a rock festival in the UK and assessed
people': hygiene over a3 day period using standardized
technique that results score ranging between (smelling
disgusting) and (smelling wonderful). Open the SPSS dataset
DownloadFestival 2.sav.
1) Create: histogram of the smell score on the first day (variable
day1)(2pts)
2) Conduct an independent I-test to determine if there is a
differene hygiene between men and women the first day
of the festival. Can assume homogeneity `variance?
Why why not? (Don't forget to write your null
alternative rypotheses. alpha. your results, and your
conclusion. Your results must contain the mean and standard
deviation of each group and t(df) XXX, pts)

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Part I—Calculate By Hand

1. If the alpha level is changed from α = 0.05 to α = 0.01,

a) What happens to the boundaries for the critical region? (2 pts)

The boundaries of the critical region would get more far away from the mean of the distribution (the middle line).

In other words - rejection of the null hypothesis would get more difficult allowing only 1% of the whole distribution, rather than 5%.

b) What happens to the probability of Type I error? (2 pts)

The probability of a Type I error would decrease from 0.05 to 0.01....