Statistics and Probability Answers

Suppose the correlation coefficient is 0.80 and the number of observations is 62. What is the calculated test statistic? Is this significant correlation using a 1% level of significance? 2. Given that, r = 0.475 N = 10, Is this significant correlation between X and Y using a 5% level of significance? 

1. Nine determinations of the specific heat of iron had a standard deviation of 0.0086. Assuming that these determinations constitute a random sample from a normal population, test the null hypothesis σ = 0.0100 against the alternative hypothesis σ < 0.0100 at the α = .05 significance level. (Hint: What is the relation between standard deviation and variance?) 2. In a random sample, the weights of 24 Black Angus steers of a certain age have a standard deviation of 238 pounds. Assuming that the weights constitute a random sample from a normal population, test the null hypothesis σ = 250 pounds against the two-tailed alternative 휎6= 250 pounds at the α = .01 significance level.

EMC research conducted a poll between Jan. 14 and Jan 22 2014. They asked a SRS of 805 voting Seattlites if they supported the minimum raise hike to $15/hr. They found a sample proportion of 68%. What is a 95% confidence interval for the true proportion? 2. EMC research conducted a poll between Jan. 14 and Jan 22 2014. They asked a SRS of 805 voting Seattlites if they supported the minimum raise hike to $15/hr. They found a sample proportion of 68%. What is a 90% confidence interval for the true proportion?

Suppose that the mean for the current gas prices in $3.00 with the standard deviation $0.25. Construct an interval that will contain 90% of all sample means of all random samples of size 40. 2. Suppose that you asked 40 people in different parts of San Diego and found that the mean price of gas that they bought this week was $3.04. Assume that population standard deviation is known to be $0.25. Construct a 90% confidence interval for the true mean of the gas price.

On average a University Book Shop sells 300 text books per day with a standard deviation of 50 text books. Find the probability that the University Book Shop will sell at least 400 text books per day

A manufacturer has observed that the time that elapses between the placement of an order with a just-in-time supplier and the delivery of parts is uniformly distributed between 100 and 180 minutes. a) What proportion of orders takes between 2 and 2.5 hours to be delivered? b) What proportion of orders takes between 2 and 3 hours to be delivered? c) What is the expected delivery time? d) What is the standard deviation of the delivery time? e) The contract between the manufacturer and supplier stipulates that the cost of the order will be $4,000 minus ten dollars per minute that it takes between the order and the delivery. What is the expected cost of an order? What is the standard deviation of the order cost? What is the probability that a continuous random variable X takes on any

A hot line with a full free number receives an average of 4 calls per hour for any given hour.  Find the probability that it will receive exactly 5 calls

Find the probability of exactly one 5 when a die is rolled 3 times 2) Find the probability of getting 3 heads when 8 coins are tossed. 3) A bag contains 4 red and 2 green balls. A ball is drawn and replaced 4 times. What is the probability of getting exactly 3 red balls and 1 green ball.

For a badminton doubles game, 2 players are chosen from among 5 male players and 3 female players to represent a club. In how many ways can this doubles pair be selected if 13.3.6 The team is a mixed double, comprising one male player and one female player? 13.3.7 The team is either a male pair or a female pair and no mixed pair is allowed?

A father buys nine different toys for his four children. In how many ways can he give one child three toys and the remaining three children two toys each? 5. A party of nine people consists of five men and four women, and a group of four people is to be chosen at random from this party. In a how many ways can a group of four be chosen that contains at least three women?