Statistics and Probability Answers

At a suburban shopping mall 70% of customers pay by ecocash.Find the probability that in a randomly selected sample of ten customers : exactly 3 pay by ecocash and more than 6 pay by ecocash

europeans have a mean paid vacation each of six weeks. what is the null and alternative hypothesis of it

P(z<1.46)

Akosua works as the customer service officer at the Agarwal Eye Clinic located in Tesano, a suburb of

the Greater Accra region. The number of requests from male patients for emergency eye treatment that

she receives during any day may be modeled by a poisson distribution with mean of 2.6.Find the

probability that the number of requests from male patients for emergency eye treatment that Akosua

receives on a particular day is;

(i) Exactly 4

(ii)At least 1

(b) Find the probability that the number of requests from male patients for emergency eye

treatment that Akosua receives during a period of 5 days is 15 or fewer

. A new machine is being considered to replace the old machine being used. This new machine was tested for 10 consecutive hours with the following output: 119, 122, 118, 122, 120, 124, 126, 125, 125, and 124. If the average output per hour using the old machine is 120 units, is the management justified in stating that the output per hour can be increased with the new machine? Use a 0.01 level of significance.

An educational researcher found that the average entrance core of the incoming freshmen in a university is 84. A random sample of 24 students from a public school was then selected and found out that their average score in the entrance exam is 88 with a standard deviation of 16. Is there any evidence to show that the sample students from public school performed better than the rest in the entrance examination using the 0.01 level of significance?

A random sample of 100 recorded deaths in the United States during the past year showed an average life span of 71.8 years, with a standard deviation of 8.9 years. Does this seem to indicate that the average life span today is greater than 70 years? Use a 0.05 level of significance. The computed value is

The sample space contains 6 As and 4 Bs. What is the probablity that a randomly selected set of 3 will include 2 As and 1 B​?

A. Find the length of the confidence interval (s = standard deviation)

1. s = 3

n = 250

Confidence level = 95%

2. s = 6

n = 400

Confidence level = 99%

B. Determine the sample size, given the following data.

1. s = 5

E = 2.42

Confidence level = 95%

2. You want to estimate the mean gasoline price within your town to the margin of error of 6 centavos. Local newspaper reports the standard deviation for gas price in the area is 30 centavos. What sample size is needed to estimate the mean gas prices at 99% confidence level?

3. Carlos wants to replicate a study where the highest observed value is 14.8 while the lowest is 14.2. He wants to estimate the population mean µ to the margin of error of 0.025 of its true value. Using 95% confidence level, find the sample size n that he need.

A. Find the length of the following confidence interval.

1. Upper limit = 0.995

Lower Limit = 0.437

2. Upper limit = 394.14

Lower Limit = 354.74

3. Upper limit = 0.02946

Lower Limit = 0.02244

4. 0.475 < p < 0.735

5. 0.355 < p < 0.570