Statistics and Probability Answers

What proportion of asthma patients are allergic to house dust? In a sample of 140, 35 percent had positive skin reactions. Construct the 95 percent confidence interval for the population proportion.

1.What is the level of measurement for

The height of people is a sample of airplane passengers.(nominal,ratio,interval,ordinal) why

2.Summary of passengers in ferry.

Man Woman Boy Girl

Survive 447 433 44 42

Dead 1475 418 50 33

i.the probability of getting a child or someone who survived the sinking(with steps)

ii.the probability of getting a woman or someone who did not survived the sinking. (with steps)

iii.What is the probability of getting a man or woman, given that the randomly selected person is someone who died? (with steps)

iv.If we randomly select someone who died, what is the probability of getting a man? (with steps)

2. The shelf life of a particular dairy product is normally distributed with a mean of 12 days and a standard deviation

of 3 days.

a) About what percent of the products last between 9 and 15 days?

b) About what percent of the products last between 12 and 15 days?

c) About what percent of the products last 6 days or less?

A recent study found that the average cost of an emergency room visit was $1,200 with a standard deviation of $250. If a patient is selected at random, what is the probability that the person’s visit will cost more than $1,600?

Find the null and alternative hypothesis of the following and identify the type of hypothesis testing:

1.) It has been known that a fixed dosage of a certain medicine results to an average increase of pulse rate by at least 12 beats per minute with a standard deviation of 5. A group of 10 patients given the same dose has shown the following pulse rate increases: 15, 10, 12, 11, 9, 10, 17, 14, 15, and 7. Is there proof to show that this group has a lower average increase of pulse than the others in general?

2.) Fifty senior high school students in Statistics got an average grade of 94 with a standard deviation of 2 while another group of 60 senior high school students got an average grade of 92 with a standard deviation of 3. Can the difference in the mean grade be attributed to chance using a 0.04 level of significance?

In six attempts it took a locksmith 9, 14, 7, 8 11, 5 seconds to open a certain kind of lock. Construct a 95% confidence interval for the average it takes the locksmith to open this kind of lock.

Suppose and LED light manufacturer want to set a lifespan guarantee on its new LED light. life test revealed that the mean of 50,000 life hours and the standard deviation of the normal distribution of 2,140 hours, The manufacturer wants to set the guaranteed life hours so that no more than 5% of the LED lights will have to be replaced. What guaranteed life hours should the manufacturer announce?

Given a normal distribution with a standard deviation of 14, what is the mean if 40% of the values are below 60?

A random or unbiased assignment of individuals or items to treatment groups in order to average out extraneous factor is called

Scores on a scholarship aptitude examination for senior high school student in a top university in the Visayas are normally distributed with a mean of 70 and standard deviation of 10. What is the highest score that will place an applicant in the bottom 30% (30th percentile) of the distribution?