Statistics and Probability Answers

The histogram graphically shows the presence of outliers and presence of multiple modes in the data. T/F

Three groups if children contains respectively 3 girls and 1 boy, 2 girls and 2 boys, and 1 girl and 3 boys. One child is selected at random from each group. Show that the chance that 3 selected consists of 1 girl and 2 boys is 13/32.

How does probability relate to scientific statements?

The advantage of a certain blood test is that 90% of the time it is positive for patients having a certain disease. Its diadvantage is that 25% of the time it is also positive in healthy people. In a certain location 30% of the people have the disease, and anybody with a positive blood test is given a drug that cures the disease. If 20% of the time the drug produces a characteristic rash, what is the probability that a person from this location who has the rash had the disease in the first place?

A GE light bulb is supposed to last for 1200 hours. In fact, light bulbs of this type last only 1185 hours with a standard deviation of 70 hours. What is the probability that a sample of 100 light bulbs will have an average life of at least 1200 hours?

A new Firestone tire is guaranteed to last for 40,000 miles. The actual mean life of the tires is 47,000 miles with a standard deviation of 4,000 miles.

a) What is the probability that a tire will not last for 40,000 miles?
b) The Ford Motor Company uses Firestone Tires and is concerned about the performance of the tires. They conduct a study and find that out of the 120 tires they tested, the mean life was only 46,500 miles. Should the Ford Motor Company be concerned about Firestone's honesty about its tires? Provide a statistical justification for your response.

I have a probability question: There are 6 positions available for a council member and there are 13 candidates. About 300 people vote. I know also know there are 4 great candidates, 3 are not strong and 6 are questionable. My question is should I only vote for 4 good candidates or vote for 6 including 2 questionable ones. This is if I only want my four candidates to win.

A rail company knows that on average they will have 3 people ill each day. In order to make plans for replacements they have asked you to calculate the following probabilities: In a single day - (1) No employees ill (2)Two or less employees ill (3) Four or more employees ill

What if the size for each sample were increased to 20? Would a sample mean of 115 or more be considered unusual? Why or why not?

Use pair data values and the summations given to
x:& 1 & & & & 3 & 5 & & 7 & & 9
y:& 10& & & 8& & 7& & & 4& & & 2

Σx= 25;& & & Σy= 31;& & & & & Σxy= 115:& & & & Σx² = 165

a. Find the equation for the least squares regression line.
b. Predict the value of y when x is 6 using your equation