# 0.2 Practice tests (1-4) and final exams  (Page 23/36)

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33 . The screening test has a 20 percent probability of a Type II error, meaning that 20 percent of the time, it will fail to detect TB when it is in fact present.

34 . Eighty percent of the time, the screening test will detect TB when it is actually present.

## 9.3: distribution needed for hypothesis testing

35 . The Student’s t -test.

36 . The normal distribution or z -test.

37 . The normal distribution with μ = p and σ = $\sqrt{\frac{pq}{n}}$

38 . t 24 . You use the t -distribution because you don’t know the population standard deviation, and the degrees of freedom are 24 because df = n – 1.

39 . $\overline{X}~N\left(0.95,\frac{0.051}{\sqrt{100}}\right)$
Because you know the population standard deviation, and have a large sample, you can use the normal distribution.

## 9.4: rare events, the sample, decision, and conclusion

40 . Fail to reject the null hypothesis, because α p

41 . Reject the null hypothesis, because α p .

42 . H 0 : μ ≥ 29.0”
H a : μ <29.0”

43 . t 19 . Because you do not know the population standard deviation, use the t -distribution. The degrees of freedom are 19, because df = n – 1.

44 . The test statistic is –4.4721 and the p -value is 0.00013 using the calculator function TTEST.

45 . With α = 0.05, reject the null hypothesis.

46 . With α = 0.05, the p -value is almost zero using the calculator function TTEST so reject the null hypothesis.

## 9.5: additional information and full hypothesis test examples

47 . The level of significance is five percent.

48 . two-tailed

49 . one-tailed

50 . H 0 : p = 0.8
H a : p ≠ 0.8

51 . You will use the normal test for a single population proportion because np and nq are both greater than five.

## 10.1: comparing two independent population means with unknown population standard deviations

52 . They are matched (paired), because you interviewed married couples.

53 . They are independent, because participants were assigned at random to the groups.

54 . They are matched (paired), because you collected data twice from each individual.

55 . $d=\frac{{\overline{x}}_{1}-{\overline{x}}_{2}}{{s}_{pooled}}=\frac{4.8-4.2}{1.6}=0.375$
This is a small effect size, because 0.375 falls between Cohen’s small (0.2) and medium (0.5) effect sizes.

56 . $d=\frac{{\overline{x}}_{1}-{\overline{x}}_{2}}{{s}_{pooled}}=\frac{5.2-4.2}{1.6}=0.625$
The effect size is 0.625. By Cohen’s standard, this is a medium effect size, because it falls between the medium (0.5) and large (0.8) effect sizes.

57 . p -value<0.01.

58 . You will only reject the null hypothesis if you get a value significantly below the hypothesized mean of 110.

## 10.2: comparing two independent population means with known population standard deviations

59 . ${\overline{X}}_{1}-{\overline{X}}_{2}$ , i.e., the mean difference in amount spent on textbooks for the two groups.

60 . H 0 : ${\overline{X}}_{1}-{\overline{X}}_{2}$ ≤ 0
H a : ${\overline{X}}_{1}-{\overline{X}}_{2}$ >0
This could also be written as:
H 0 : ${\overline{X}}_{1}\le {\overline{X}}_{2}$
H a : ${\overline{X}}_{1}>{\overline{X}}_{2}$

61 . Using the calculator function 2-SampTtest, reject the null hypothesis. At the 5% significance level, there is sufficient evidence to conclude that the science students spend more on textbooks than the humanities students.

62 . Using the calculator function 2-SampTtest, reject the null hypothesis. At the 1% significance level, there is sufficient evidence to conclude that the science students spend more on textbooks than the humanities students.

## 10.3: comparing two independent population proportions

63 . H 0 : p A = p B
H a : p A p B

#### Questions & Answers

during a prize distribution ceremony the first 10 students of a class where are asked to take their seats in the first roar of 10 seats according to their preference .what is the probability that they will sit in the order of their ranks?
Punam Reply
10%
ATTAH
In a survey of 100 stocks on NASDAQ, the average percent increase for the past year was 9% for NASDAQ stocks.
Noor Reply
what is primary data and it's various types of collection of data?
Xaib Reply
If a random variable X takes only two values -2 and 1 such that 2 P[X=- 2]=P[X=1]=P, then find variance of x.
Dikshita Reply
2.5
Anirban
how!
Alif
can u show the solution pls?
Punam
the mean of random variable following binomial distribution is 10. the numbers of trails are 30. What the approximate value of variance?
AMIT Reply
what is chis square
Remelyn Reply
A chi-square (χ2) statistic is a test that measures how a model compares to actual observed data.
kalim
descriptive statistics basic
Sangeetha
Hi Friends
Sangeetha
tamil people yaaraavathu irukkingala
Sangeetha
what is the median of the following set of number:3,3,3,4,5,6,7,8,8,9?
Sur Reply
3
Mbemah
5.6
Alekya
(5+6)/2=5.5555.......=5.6
Lyrical
(5+6)/2=5.5 that is the median
moniba
hi friends am new here, hope am welcome
nathan
hi friends am new here, hope am welcome
nathan
1.5
nathan
differences between Intervals and Ratio measurement scales
VIP Reply
interval is the distinct from a starting point to the peak of a certain distance
Mbemah
the taking of a certain range accurately in a divisional way
Mbemah
i need the solution for exercise sums
Siva Reply
descriptive statistics sums I need
Sangeetha
statistics discovered?
Kaleem Reply
internet
Kamranali
dev OS
Virendra
searching for motivation to learn stat
Nija
purpose of of statistics
mukesh
ya..
mukesh
tamil people yaraavathu inrukkingala
Sangeetha
Odisha ru kau bhai mane achha?
Hemanta
I want to learn my MSC by statistics who can help me ?
Abebe
@Avirup interest person
Abebe
good morning
Sangeetha
Dr good morning
mukhtar
in statistical inferences we use population parameter to infer sample statistics
anupama Reply
Yes
lukman
how do we calculate decile
Drix Reply
how do we calculate class boundaries
Syed
The lower class boundary is found by subtracting 0.5 units from the lowerclass limit and the upper class boundary is found by adding 0.5 units to the upper class limit. The difference between the upper and lowerboundaries of any class.
Ekene
The lower class boundary is found by subtracting 0.5 units from the lowerclass limit and the upper class boundary is found by adding 0.5 units to the upper class limit. The difference between the upper and lowerboundaries of any class.
Ekene
complete definition plz
Zarifa Reply
what are the advantages and disadvantages of primary and secondary data
Elisha Reply
advantage of primary data 1) specific 2) Accurate 3)ownership 4)up to date information 5) control Disadvantage of primary data 1) Expensive 2) time consuming 3) feasibility.
Xaib
the average increase for all NASDAQ stocks is the
Technical Reply

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