Statistics and Probability Answers

Assume that the variable is normally distributed, the average time it takes a group of senior high school sidents to complete a certain examination is 40.2 minutes while the standard deviation is 8 minutes

What is the probability that a randomly selected senior high school students will complete the examination in less than 43 minutes? the given altuation, what words would give us a clue to the direction of the

curve or where the shaded part is located?

assuming that the sample come from the normal distributions find the margim of error. E given the following

B.n=16,X =50, s=4.2, 95% confidence

The leader of the association of jeepney drivers claims that the average daily take home pay of all jeepney drivers in a particular city is php 450. A random sample of 100 jeepney drivers in the city was interviewed and the average daily take home pay of these drivers is found to be php 500. Use a 0.05 significance level to find out if the average daily take home pay of all jeepney drivers in the city is greater than php 450. Assume that the population variance is php 8644.

The diameters of washers are normally distributed with mean 50mm and variance

4mm. A washer is considered non-defective if its diameter lies between 46mm and

53mm. If one washer is randomly selected, what is the probability that:

4.2.1 its diameter less than 45mm? (6)

4.2.2 itis defective?

There is a claim that on daily average students spend 5.5 hours on social media with standard deviation of 1.25 .A resercher wants to test the claim at 5% level significance.

1.formulate the null and alternatuve hyphothesis

2.Determine the test statistic to be used

3.Find the corresponding z value

4. Identify the rejection region

1. A researcher estimates that the average height of the buildings of 30 or more

stories in a large city is at least 700 feet. A random sample of 10 buildings is

selected, and the heights in feet are shown. At  = 0.025, is there enough

evidence to reject the claim?

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520 535 635 616 582

1. A researcher estimates that the average height of the buildings of 30 or more stories in a large city is at least 700 feet. A random sample of 10 buildings is selected, and the heights in feet are shown. At  = 0.025, is there enough evidence to reject the claim? 485 511 841 725 615 520 535 635 616 582

In student's t-distribution, if the sample size is 25, what is the degree of freedom?

II. Determine the given of the problems below and formulate the null and alternative hypothesis both in words and symbols. Write your answer in your notebook. Please follow the format in the examples.

2. A study was conducted to determine the marrying age of teachers. It was found out that the mean marrying ager of teachers is 30 years old. Fifteen teachers were surveyed randomly and found that their mean marrying age was 33 years old with a standard deviation of 5 years. Use 10% level of significance to test the hypothesis and assume that the population is normally distributed.

3. A study was conducted to determine the marrying age of teachers. It was found out that the mean marrying ager of teachers is 30 years old. Fifteen teachers were surveyed randomly and found that their mean marrying age was 33 years old with a standard deviation of 5 years. Use 10% level of significance to test the hypothesis and assume that the population is normally distributed.