Search & Filtering
Customers arrive at a shopping mart randomly at a rate of 7 per hour.
a) Find the probability that during any 90 minutes’ period, the number of customers arriving at the shopping mart is exactly 8.
b) If a customer arrives at 11.30 am, find the probability that the next patient arrives before 11.45 am.
The average on a history exam was 85 out of 100 points, with a standard deviation of 15. Was the distribution of the scores on this exam symmetric? If not, what shape would you expect this distribution to have? Explain your reasoning.
At a restaurant 80% of the users pay using credit cards. Find the probability that in a randomly selected sample of 5 users, exactly 2 users pay using credit cards.
3. What is the 99.5th percentile in a t-distribution with 9 degrees of freedom?
a. 2.764 b. 3.250 c. 3.169 d. 2.821
4. To estimate the mean price of e-books of senior high schools, with a standard deviation of P80, how many e-books are needed to be selected as samples if we wanted to be 95% confident that the sample mean of e-books is within P20 of the true population?
a. 59. b. 60 c. 61 d. 62
5. Which of the following is the appropriate sample size given a standard deviation of 6.4, confidence interval of u 98% and a margin of error or maximum allowable deviation of 2.35?
a. 39 b. 40 c. 41 d. 42
1. t - distribution is a probability distribution used to estimate parameters EXCEPT
when :
a.. the population standard deviation is known
b. the sample size is small.
d. the sample size is small and population variance is unknown
2. t distribution is also known as:
c. the population variance is unknown
a. Teacher's t distribution b. z-distribution
c. Student's t - distribution d. Teacher's z - distribution
The height of male college students are normally distributed with mean of 68 inches and standard deviation of 15 inches. If 25 students each are drawn from the population, what is the probability that;
2a) the sample mean is at least 75
2b) the sample mean is less than 59
2c) the sample mean is greater than 72
A population of PWD learners in 5 schools in a certain municipality of Quezon Province are (𝒙) 9, 5, 6, 12, and 15. Suppose that two schools were selected as samples, determine the mean and variance of the sampling distribution of sample mean.
The height of male college students are normally distributed with mean of 68 inches and standard deviation of 15 inches. If 25 students each are drawn from the population, what is the probability that;
2a) the sample mean is at least 75
2b) the sample mean is less than 59
2c) the sample mean is greater than 72
In a graduate teacher college, a survey was conducted to determine the proportion of students who want to major in Mathematics. If 378 out of 900 students said Yes, with 95% confidence, what interpretation can we make regarding the probability that all students in the teacher graduate college want to major in Mathematics.
Problem:
Mr. Domingo conducted a survey among ten random samples of people who are in favor of Truck Ban in a section in the City. He determined the percentages of those who are in favor of the ban. Assuming that the only error present is the sampling error, he wanted to determine the point estimate of the population mean percentage and the standard deviation based on 500 observations. The following numbers represent the percentages of the 10 surveys.
47.0 56.4 50.1 60.2 48.0 55.3 60.0 59.5 63.0 57.5
1. Find the sum of the values in the numerator and n-1.s2=∑(X−x)2n−1
s2=(47.0−)2+(56.4−)2+...+(57.5−)210−1
s2=
__________
This value is called the _______________________
2. Extract the square root of s2 s= _____________
This value is called the ______________________.
3. Describe/Interpret the result.On the average, the sample mean percentage is __________ away from the mean of the percentage value of people favoring the truck ban.
