2.) Find the 90% confidence intervals for population mean for the following a.) sample mean is 53 and = 7.1 for n = 90 b.) sample mean is 285 and = 7.1 for n = 28 c.) sample mean is 149.7 and s = 23.8 for n = 20
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A poll is taken in which 349 out of 500 randomly selected voters indicated their preference for a certain candidate. (a) Find a 99% confidence interval for p. ≤p≤ (b) Find the margin of error for this 99% confidence interval for p.
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A normal distribution has a mean of µ = 28 with σ = 5. Find the scores associated with the following regions:
a. the score needed to be in the top 41% of the distribution b. the score needed to be in the top 72% of the distribution c. the scores that mark off the middle 60% of the distribution
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A teacher is explaining to her class the concepts of genetics regarding eye color.
She assumes that categories will have the following proportions: Blue = 20%, Green = 10%, Brown = 50%, Hazel = 20%
Use a 0.05 level of significance.
Here are the results for the class.
Observed Eye Colors: Blue=4; Green=3; Brown= 9, Hazel= 4,
What test are you running?
What are the observed values for the blue eye, brown eye, hazel eye color?
What are the expected values for the blue eye color, green eye color, brown eye color, and hazel eye color?
What are the degrees of freedom?
What is the null hypothesis?
What is the alternative hypothesis?
What is the test statistic? Use one decimal place.
What is the p-value? Use three decimal places.
What is your conclusion based on the p-value and the level of significance?
At the 5% significance level, what can you conclude?
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According to a poll of Canadian adults, about 55% work during their summer vacation. Consider a sample of 150 adults,
a. What is the probability that between 49 and 60% of the sampled adults work during the summer vacation?
b. What is the probability that over 62% of the sampled adults work during summer vacation?
c. Calculate a 95% CI for the population proportion p.
d. We would need to calculate a [X]% CI to modify the margin of error to 0.1418.
e. In order to maintain the 95% CI while having a margin of error equal 0.1418, we need to change our sample size from 150 to [X].
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An underprepared student takes a 8 question multiple choice quiz by guessing every answer. There are 5 choices (a,b,c,d,e). answer the following... what is p1, p2 and n (a). the average number of correct questions. (b). the standard deviation in correct question. (c) the probability of no questions correct. (e) the probability of getting at least 1 correct. (f) the probability of getting fewer than 3 questions correct. (g) the probability of getting exactly half correct.
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A manager wishes to see if the time (in minutes) it takes for their workers to complete a certain task is faster if they are wearing ear buds. A random sample of 20 workers' times were collected before and after wearing ear buds. Test the claim that the time to complete the task will be faster, i.e. meaning has production increased, at a significance level of α = 0.01
For the context of this problem, μ_{D} = μ_{before}−μ_{after} where the first data set represents before ear buds and the second data set represents the after ear buds. Assume the population is normally distributed. The hypotheses are:
H_{0}: μ_{D} = 0
H_{1}: μ_{D} > 0
You obtain the following sample data:
Before |
After |
69 |
62.3 |
71.5 |
61.6 |
39.3 |
21.4 |
67.7 |
60.4 |
38.3 |
47.9 |
85.9 |
77.6 |
67.3 |
75.1 |
59.8 |
46.3 |
72.1 |
65 |
79 |
83 |
61.7 |
56.8 |
55.9 |
44.7 |
56.8 |
50.6 |
71 |
63.4 |
80.6 |
68.9 |
59.8 |
35.5 |
72.1 |
77 |
49.9 |
38.4 |
56.2 |
55.4 |
63.3 |
51.6 |
a) Find the p-value. Round answer to 4 decimal places.
Answer:
b) Choose the correct decision and summary.
Do not reject H_{0}, there is enough evidence to support the claim that the time to complete the task has decreased when workers are allowed to wear ear buds at work. |
Do not reject H_{0}, there is not enough evidence to support the claim that the time to complete the task has decreased when workers are allowed to wear ear buds at work. |
Reject H_{0}, there is enough evidence to support the claim that the time to complete the task has decreased when workers are allowed to wear ear buds at work. |
Reject H_{0}, there is not enough evidence to support the claim that the time to complete the task has decreased when workers are allowed to wear ear buds at work. |
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A trucking company determined that the distance traveled per truck per year is normally distributed, with a mean of 80 thousand miles and a standard deviation of 10 thousand miles. Complete parts (a) through (c) below. a. nbsp What proportion of trucks can be expected to travel between 66 and 80 thousand miles in a year? The proportion of trucks that can be expected to travel between 66 and 80 thousand miles in a year is . 4192. (Round to four decimal places as needed.) b. nbsp What percentage of trucks can be expected to travel either less than 55 or more than 95 thousand miles in a year? The percentage of trucks that can be expected to travel either less than 55 or more than 95 thousand miles in a year is 7.30%. (Round to two decimal places as needed.) c. nbsp How many miles will be traveled by at least 85% of the trucks? The amount of miles that will be traveled by at least 85% of the trucks is nothing miles. (Round to the nearest mile as needed.)
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A random sample of 1600 workers in a particular city found 432 workers who had full health insurance coverage. Find a 95% confidence interval for the true percent of workers in this city who have full health insurance coverage. Express your results to the nearest hundredth of a percent. .
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The null and alternate hypotheses are:
H_{0} : μ_{d} ≤ 0
H_{1} : μ_{d} > 0
The following sample information shows the number of defective units produced on the day shift and the afternoon shift for a sample of four days last month.
Day | ||||
1 | 2 | 3 | 4 | |
Day shift | 11 | 12 | 14 | 18 |
Afternoon shift | 8 | 9 | 13 | 16 |
At the 0.025 significance level, can we conclude there are more defects produced on the day shift? Hint: For the calculations, assume the day shift as the first sample.
State the decision rule. (Round your answer to 2 decimal places.)
Compute the value of the test statistic. (Round your answer to 3 decimal places.)
What is the p-value?
Between 0.005 and 0.01
Between 0.001 and 0.005
Between 0.01 and 0.025
What is your decision regarding H_{0}?
Reject H_{0}
Do not reject H_{0}
rev: 08_30_2017_QC_CS-97216, 11_25_2017_QC_CS-109804
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independent random sample of size n1=16 and n2= 25 from a normal population with standard deviation1=4.8 and standard deviation 2=3.5 have the mean x bar1=18.2 and xbar2=23.4 find the 90% confidence interval for mew1-mew 2
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Lay out the design for two between-subjects experiments: a) an experiment involving two experimental groups and a control group, and b) a factorial design with three independent variables that have three, and two levels respectively.
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White boxers are dogs that have a genetic disposition for going deaf within the first year after they are born. Suppose a litter of seven white boxer puppies contained three dogs that would eventually experience deafness. A family randomly selected puppies from this litter to take home as family pets. (For this problem, define a success as selecting a dog that will eventually experience deafness.) (Round to three decimal places as needed.)
a. Determine the probability that none of the three puppies selected will experience deafness.
b. Determine the probability that one of the three puppies selected will experience deafness.
c. Determine the probability that all three puppies selected will experience deafness.
(Round to four decimal places as needed.)
d. Calculate the mean and standard deviation of this distribution.
The mean of this distribution is
(Round to three decimal places as needed.)
The standard deviation of this distribution is
(Round to three decimal places as needed.)
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Pre-confinement (Hz) |
Confined (Hz) |
10.4 |
9.6 |
10.3 |
10 |
10.8 |
10.3 |
10.5 |
9.9 |
11 |
10.5 |
10.6 |
9.2 |
10.4 |
9 |
9.7 |
9.8 |
11.2 |
9.8 |
12.2 |
9.1 |
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The graph illustrates a normal distribution for the prices paid for a particular model of HD television. The mean price paid is $1000 and the standard deviation is $145.
What is the approximate percentage of buyers who paid between $1000 and $1290? 47.5 Correct%
What is the approximate percentage of buyers who paid between $1000 and $1145? 34 Correct%
What is the approximate percentage of buyers who paid less than $565? -.335 Incorrect%
What is the approximate percentage of buyers who paid less than $710? -2.685 Incorrect%
What is the approximate percentage of buyers who paid between $1000 and $1435? 49.85 Correct%
What is the approximate percentage of buyers who paid between $855 and $1145? 68 Correct%
In: Math