Math Answers

Five hundred children participated in a field demonstration. Their heights averaged 110cm with a standard deviation of 6cm.

1. What is the probability that a child picked at random has a height greater than 116cm?

2. What is the probability that the height of a child picked at random is less than 104cm?

3. What is the probability that the height of a child picked at random is between 110cm and 122cm?

4. How many children have heights between 98 and 104cm?

5. How many children belong to the upper 15% of the group?

A population consists of the five measurements 2,6,8,3 & 1. How many different samples of size n=2 can be drawn from the population? What is the mean and variance of the sampling distribution of the sample means? Follow the steps1to 6

A vacant lot has the shape of a trapezium having sides 8m, 12m, 18m, and 20m . If the sum of of the opposite angles is 230⁰ , find the area of the lot in square meters

A shipment of five computers contains two that are slightly defective. If a retailer receives three of these computers at random, list the elements of the sample space S using the letters D and N for defective and non-defective respectively. To each sample point, assign a value x of the random variable X representing the number of computers purchased by the retailer which are slightly defective

Give an example of relation which is Reflexive, anti symmetric & transitive but not symmetric

Random samples with size 30 are drawn from the population with a mean of 25 and a standard deviation of 7. Find the mean and the standard error of the sample mean.

The average monthly electricity bill of households in a particular subdivision is Php3 000 with standard deviation of Php800. Suppose the monthly electricity bill follows a normal distribution. What is the probability that the average monthly electricity bill of 15 households is more than Php3 200?

A certain university produced 895 licensed teachers after they successfully passed the Licensure Examination for Teachers (LET). The professional Regulation Commission (PRC) records show that the examinees form that university posted an average rating of 85 with standard deviation of 2. If 36 successful examinees are selected at random, what is the probability that their ratings fall between 84 and 86?

A random sample of 60 students is chosen from a large population with an average diastolic blood pressure of 100 and a standard deviation of 36. What is the probability that the mean diastolic blood pressure of these 60 students is less than 110?

The average time spent in a week by grade 11 students browsing their favorite social networking sites is 12 hours with a standard deviation of 3 hours. If a random sampling of 40 students is selected, find the mean, variance, and standard error of the distribution of all sample means that can be derived from the sample.