Statistics and Probability Answers

An automobile manufacturer has discovered that 20% of all the transmissions it installed in a particular style of truck one year are defective. It has contacted the owners of these vehicles and asked them to return their trucks to the dealer to check the transmission. The Friendly Auto Mart sold seven of these trucks and has two of the new transmissions in stock. What is the probability that the auto dealer will need to order more new transmissions?

A bag contains 3 R and 3 G balls and a person draws out 3 at random. he then drops three balls into the bag and again draws out 3 at random. the chance that 3 later balls being all of different colours is

a market researcher for a provider of ipod accessories wants to know the proportion of customers who own cars to access the market for a new ipod car charger. a survey of 500 customers indicates that 76% own cars

How large would the standard deviation have to be if he had surveyed only 125 customers assuming the proportion is about the same?

A multichannel microwave link is to provide telephone communication to a remote community having 12 subscribers, each of whom uses the link 20% of the time during pick hours. How many channels are needed to make the link available during pick hours to:
(a) Eighty percent of the subscribers all of the time?
(b) All of the subscribers 80% of the time?
(c) All of the subscribers 95% of the time?

A die has four of its faces coloured white and the remaining two coloured black. What is the probability that when the die is thrown two consecutive times, the top face will be white in both cases ?

13

49

920

13

You find that there are 72 multiple-choice questions with three possible responses (A, B, or C) for each, where only one is correct. The passing grade is set at 50%. Unluckily for you, you haven’t been to a single class before this, nor have you ever opened the textbook. Actually, you can’t even say for sure who the guy is at the front of the class. You will have to guess the answer on all the questions. What is the probability that you will pass the exam?

For the previous problem, The sample of 100 screws turns out to have mean = 15.005mm. (Still testing against = 15 mm and assuming population standard deviation is known to be 0.04mm.) Does this give evidence that the lengths of the screws are longer than 15mm? Explain using the important values you use to make your decision.

In 2014 the Department of Social Services reported that 32% of current marriages in Australia were expected to end in divorce.
Find the probability that more than 8 marriages out of a random sample of 20 marriages which were current in 2014 would end in divorce.

In 2014 the Department of Social Services reported that 32% of current marriages in Australia were expected to end in divorce.
Find the probability that more than 8 marriages out of a random sample of 20 marriages which were current in 2014 would end in divorce.

Two-sample T for MetRate
SE
Sex N Mean StDev Mean
Male 75 1626 227 26
Female 75 1258 172 20

Difference = μ (Male) - μ (Female)
Estimate for difference: 367.9
95% CI for difference: (****, ****)
T-Test of difference = 0 (vs ≠): T-Value = **** P-Value = **** DF = ****
Both use Pooled StDev = 201.5088

Is there a difference between the average metabolic rate of adolescent males and adolescent females?
Hypothesis Test: