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Basic Statistics Concepts and Hypothesis Testing

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1. A mean score of 5.4 with SD of 1.6, where would 68% fall? a.between 3.8 and 7.0 or b.between 5.4 and 7.0?
2.Descriptive stats related to variabitity helps you evaluate what of a sample? a.the homogeneity or heterogeneity of the sample, b.the sampling error,c.the t test or d.meta analysis
3.is rating job satisfaction on 5 point scale 1=very satisfied, etc ordinal?
4.what does a SD of 3.73mean in terms of scores?
5. If the SD score was larger, how would you interpret the score in terms of homogeneity or heterogeneity of the sample? (study critical thinking in nursing students on a six item measure)
If females and males have mean score of 23 on critical thinking test but females had a SD of 7 and males of 3, what can you conclude about the males in terms of homogeneity of the sample?
6.what is a null hypothesis in a group a and group b(one gets flu shots and one nil)

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1.
According to the 68-95-99.7 rule, 68% of the data falls within 1 SD from the mean.
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1. A mean score of 5.4 with SD of 1.6, where would 68% fall? a. between 3.8 and 7.0 or b. between 5.4 and 7.0?
Solution:
According to the 68-95-99.7 rule, 68% of the data falls within 1 SD from the mean.

Thus for the given distribution, 68% of the data is expected to fall between 3.8 and 7.0.

2. Descriptive stats related to variability helps you evaluate what of a sample? a. the homogeneity or ...

Solution Summary

The expert examines basic statistics concepts and hypothesis testing.

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Basic Statistics: Calculations for Hypothesis Testing & Probability

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I'm having difficulties setting up the problems, I'm understanding the formulas and concepts, but I would really appreciate your help!

For Questions 3 & 4, complete the following:
a) State the null and alternate hypotheses. Will we use a left-tailed, right-tailed, or two-tailed test? What is the level of significance?
b) Identify the sampling distribution to be used: standard normal or the Student's t. Compute the z or t value of the sample test statistic and sketch its location.
c) Find the P value for the sample test statistic.
d) Should we reject or fail to reject the null hypothesis?

Question 3
How productive are employees? One way to answer this question is to study annual company profits per employee. Let x1 represent annual profits per employee in computer stores in St. Louis. A random sample of n1 = 11 computer stores gave a sample mean of x1 = $25,200 profit per employee with sample standard deviation s1 = $8,400. Another random sample of n2 = 9 building supply stores in St. Louis gave a sample mean x2 = $19,900 per employee with sample standard deviation s2 = $7,600. Does this indicate that in St. Louis computer stores tend to have higher mean profits per employee? Use α = 0.01. (50 pts)

Question 4
A telemarketer is trying two different sales pitches to sell a carpet cleaning service. For Sales Pitch I, he contacted 175 people and 62 of these people bought the cleaning service. For Sales Pitch II, he contacted 154 people and 45 of these people bought the cleaning service. Does this indicate that there is any difference in the population proportions of the people who will buy the cleaning service, depending on which sales pitch he uses? Use α = 0.05. (50 pts)
Question 5
Weights of a certain model of fully loaded gravel trucks follow a normal distribution with a mean of 6.4 tons and a standard deviation of 0.3 tons. What is the probability that a fully loaded truck of this model is (45 points)
a. Less than 6 tons?
b. More than 7 tons?
c. Between 6 and 7 tons?

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