# 0.2 Practice tests (1-4) and final exams  (Page 26/36)

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21 . In a sample of 25 cases, two variables have a correlation of 0.45. Do a t -test to see if this result is significant at the α = 0.05 level. Use the formula:
$t=\frac{r\sqrt{n-2}}{\sqrt{1-{r}^{2}}}$

## 12.7: prediction

Use the following information to answer the next two exercises. A study relating the grams of potassium ( Y ) to the grams of fiber ( X ) per serving in enriched flour products (bread, rolls, etc.) produced the equation:
$\stackrel{^}{y}=25+16x$

22 . For a product with five grams of fiber per serving, what are the expected grams of potassium per serving?

23 . Comparing two products, one with three grams of fiber per serving and one with six grams of fiber per serving, what is the expected difference in grams of potassium per serving?

## 12.8: outliers

24 . In the context of regression analysis, what is the definition of an outlier, and what is a rule of thumb to evaluate if a given value in a data set is an outlier?

25 . In the context of regression analysis, what is the definition of an influential point, and how does an influential point differ from an outlier?

26 . The least squares regression line for a data set is $\stackrel{^}{y}=5+0.3x$ and the standard deviation of the residuals is 0.4. Does a case with the values x = 2, y = 6.2 qualify as an outlier?

27 . The least squares regression line for a data set is $\stackrel{^}{y}=2.3-0.1x$ and the standard deviation of the residuals is 0.13. Does a case with the values x = 4.1, y = 2.34 qualify as an outlier?

## 13.1: one-way anova

28 . What are the five basic assumptions to be met if you want to do a one-way ANOVA?

29 . You are conducting a one-way ANOVA comparing the effectiveness of four drugs in lowering blood pressure in hypertensive patients. What are the null and alternative hypotheses for this study?

30 . What is the primary difference between the independent samples t -test and one-way ANOVA?

31 . You are comparing the results of three methods of teaching geometry to high school students. The final exam scores X 1 , X 2 , X 3 , for the samples taught by the different methods have the following distributions:
X 1 ~ N (85, 3.6)
X 1 ~ N (82, 4.8)
X 1 ~ N (79, 2.9)
Each sample includes 100 students, and the final exam scores have a range of 0–100. Assuming the samples are independent and randomly selected, have the requirements for conducting a one-way ANOVA been met? Explain why or why not for each assumption.

32 . You conduct a study comparing the effectiveness of four types of fertilizer to increase crop yield on wheat farms. When examining the sample results, you find that two of the samples have an approximately normal distribution, and two have an approximately uniform distribution. Is this a violation of the assumptions for conducting a one-way ANOVA?

## 13.2: the F Distribution

Use the following information to answer the next seven exercises. You are conducting a study of three types of feed supplements for cattle to test their effectiveness in producing weight gain among calves whose feed includes one of the supplements. You have four groups of 30 calves (one is a control group receiving the usual feed, but no supplement). You will conduct a one-way ANOVA after one year to see if there are difference in the mean weight for the four groups.

Suppose from the 1,000 freshmen that took the entrance examination, it was found out that the standard deviation was 10 a. How many students passed the test if the passing score is set 75? b. What scores comprise the middle 95% of all scores?
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Sweet
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?
10%
ATTAH
In a survey of 100 stocks on NASDAQ, the average percent increase for the past year was 9% for NASDAQ stocks.
what is primary data and it's various types of collection of data?
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.
2.5
Anirban
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Alif
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Punam
the mean of random variable following binomial distribution is 10. the numbers of trails are 30. What the approximate value of variance?
what is chis square
A chi-square (χ2) statistic is a test that measures how a model compares to actual observed data.
kalim
descriptive statistics basic
Sangeetha
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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?
3
Mbemah
5.6
Alekya
(5+6)/2=5.5555.......=5.6
Lyrical
(5+6)/2=5.5 that is the median
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nathan
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nathan
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nathan
differences between Intervals and Ratio measurement scales
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
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descriptive statistics sums I need
Sangeetha
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internet
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Virendra
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Nija
purpose of of statistics
mukesh
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mukesh
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Hemanta
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Abebe
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Abebe
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Sangeetha
Dr good morning
mukhtar
in statistical inferences we use population parameter to infer sample statistics
Yes
lukman
how do we calculate decile
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
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.
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