Statistics and Probability Answers

A researcher hypothesizes that people who listen to music via headphones have greater hearing loss and will thus score lower on a hearing test than those in the general population. On a standard hearing test u=19.2. The researcher gives this same test to a random sample of 12 individuals who regularly use headphones. Their scores on the test are 17,15,21,13,26,23,24,20,18,18,22,21. What is the tcv? compute t obt

Bio Chemical Oxygen Demand(BOD) concentration depends upon
velocity of flow. Work out the appropriate mean value from the data of
velocity of flow ( m/s) and BOD values given below.
5.0, 9.0, 6.0, 40.0, 2.0, 6.0, 3.0, 10.0, 5.0, 3.0, 7.0 BOD ( mg/l;)
0.8 1.0 1.2 1.4 1.0 1.3 1.0 1.4 1.2 1.0 0.9 Vel( m/S)
What statistic will you compute?

The probability of a shooter hitting a target is 2/4 . How many minimum number of times must he/she fire so that the probability of hitting the target at least once is more 0.99?

A researcher wants to compare users of marijuana to users of crack cocaine to see if they differ in whether they are referred to drug courts after arrest. What type of statistical test should be used to conduct this analysis?

Suppose we have a binomial experiment in which success is defined to be a particular quality or attribute that interests us.
(a) Suppose n = 36 and p = 0.23. Can we approximate p̂ by a normal distribution? Why? (Use 2 decimal places.)
np =
nq =

, p̂ be approximated by a normal random variable because .

What are the values of μp̂ and σp̂? (Use 3 decimal places.)
μp̂ =
σp̂ =

(b) Suppose n = 25 and p = 0.15. Can we safely approximate p̂ by a normal distribution? Why or why not?
, p̂ be approximated by a normal random variable because .

(c) Suppose n = 58 and p = 0.21. Can we approximate p̂ by a normal distribution? Why? (Use 2 decimal places.)
np =
nq =

, p̂ be approximated by a normal random variable because .

What are the values of μp̂ and σp̂? (Use 3 decimal places.)
μp̂ =
σp̂ =

A committee of 5 is to be formed from among 6 doctors, 5 CAs, 2 MBAs and 1 Government employee. Find the probability such that (i) each

profession is represented (ii) the committee has 1 Government employee and at least one MBA.

Suppose three cell phones are tested randomly. We want to find out the number of defective cellphones that occur.
Let D represent the defective and N for non-defective cell phone. If we let X be the random variable representing the number of cell phones, can you show the values of random variable X?

Find the probability ​P(Ec​) if ​P(E)equals=0.23.
The probability ​P(Ec​) is

For each of the following situations, find an interval that contains (approximately or exactly) 99.73 percent of all the possible sample means. In which cases must we assume that the population is normally distributed? Why?

The height of 40 students were measured and recorded as follows;

38.7 40.2 55.4 60.9 70.1 72.5 50.4 63.7
39.4 54.6 59.3 60.2 45.1 66.5 37.9 74.2
44.5 59.6 55.2 60.7 68.0 70.0 71.2 48.3
49.4 54.4 60.9 64.7 69.3 57.4 46.2 68.9
55.3 70.2 71.7 63.2 55.4 39.0 40.3 44.5

Using classes of 35-39, 40-44,- - - calculate;
i. The arithmetic mean
ii. The standard deviation