Statistics and Probability Answers

1. Suppose X is normally distributed with a mean of 5 and a standard deviation of 0.4.Using

  the standard score formula,we findP(X ≤ Xo)=P(Z ≤ 1.3).What is the value of Xo?

1.The population of SULU Horn bill (one of the endangered bird species in the Philippines) has a standard deviation of 40. An environment researcher wants to construct a 90% confidence interval if the sample size is 150 and the sample mean is 65.

a. What is the margin of error

b. Construct the confidence interval

c. Find the leng of the confidence interval

2. The average price of 350 cellphones is Php 13,500 with a sample standard deviation of Php 750. A market researcher desires a 99% level of confidence in the true average price of cellphones

a. What is the margin error

b. Construct the confidence interval

c. Find the length of the confidence interval

Given

1. E = 0.03, 0 =

o = 0.57,

90% confidence

2. E = 0.15, o = 1.2,

95% confidence

3. E = 0.05, o = 0.45,

99% confidence

n=

n=

n=

Solution and Answer

Activity 2: Maximum Error E

Activity 2: Maximum Error E

Assuming that the samples come from a normally distributed population, find

the maximum error E given the following:

Given

Solution and Answer

1.

n = 10, X= 28, s = 4.0,

90% confidence

2. n = 16, X= 50, s = 4.2,

95% confidence

3. n = 25, X= 92.8, s = 2.6,

99% confidence

Assuming that the samples come from a normally distributed population, find

the maximum error E given the following:

Given

Solution and Answer

1.

n = 10, X= 28, s = 4.0,

90% confidence

2. n = 16, X= 50, s = 4.2,

95% confidence

3. n = 25, X= 92.8, s = 2.6,

99% confidence

Suppose in a dice game, the person who rolls two dice wins if his rolls results in a pair of numbers whose sum is 7 or 11. In how many ways can he or she win

the random variable Y, representing the number of nuts in a chocolate bar has the following probability distribution. compute the mean. K= 0,1,2,3,4 P(K)= 1/10,3/10,3/10,2/10,1/10

5. The frequency distribution shows the salaries in million for specific year of top 25ceo’s in United States. Find the mean, variance and standard deviation. 

Class Boundaries Frequency 

15.5-20.5 13 

20.5-25.5   6 

25.5-30.5   4 

30.5-35.5 1 

35.5-40.5 1 

between z= 0 and z =1.36

Findi the length of the following confidence interval

1. Upper confidence limit = 0.622

Lower confidence limit = 0.465

Suppose that 4% of all TVs made by A&B Company in 2000 are defective. If eight of 

these TVs are randomly selected from across the country and tested, what is the 

probability that exactly three of them are defective? Assume that each TV is made 

independently of the others.