Mean
It is a variable being measured to produce numerical observations associated with the random outcomes of a chance experiment.
Random variable
A variable whose value could be a finite and countable number
discrete random variable
Which of the following is a discrete random variable?
A. the number of patients in a hospital
B. the average amount of electricity consumed
C. the average weight of female athletes
D. the amount of paint used in repainting a building
A. the number of patients in a hospital
Which of the following is NOT a discrete variable?
A. The weight of box delivered by the Shopee rider last December
B. The number of non-defective laptops
C. The number of vehicles owned by Teves’s family
D. The number of coins that match when three coins are tossed at once.
A. The weight of box delivered by the Shopee rider last December
Which of the following statements describes a continuous variable?
A. The number of students who have not returned the modules
B. The average speed travelled by a van in a month
C. The number of motorists not wearing helmet
D. The number of parents who are very cooperative in the Learning Continuity Plan of the DepEd
B. The average speed travelled by a van in a month
Which of the following is NOT a continuous variable?
A. The number of arrivals at an emergency room between 8am to 8pm
B. The temperature of a cup of tea served at a restaurant
C. The weight in pounds of a bag of powdered milk as relief good last month
D. The average height of “rubber trees” along Rovera Street
A. The number of arrivals at an emergency room between 8am to 8pm
You decide to conduct a survey of families with two children. You are interested in counting the number of boys (out of two children) in each family. Is the above experiment “counting the number of boys (out of 2 children) in each family a random variable?
A. Yes, it is a random variable.
B. No, it is not a random variable.
C. Maybe
D. It cannot be determined.
A. Yes, it is a random variable.
What are the possible values of a random variable when a coin is tossed once?
A. Tail (T) and Head (H)
B. The number of dots 1,2,3,4,5,6
C. Tail and Tail (TT), and Head and Head (HH)
D. The pair of even number of dots (2,2),(2,4),(2,6),(4,2),(4,4),(4,6),(6,2),(6,4) and (6,6)
A. Tail (T) and Head (H)
If a coin is tossed, what are the possible values of the random variable for the number of tails?
A. 0,1,2,3 B. 1,2,3 C. 0,1,2 D. 0,1
D. 0,1
Which of the following values is NOT the value of the probability of the random variable?
A. 1.05 B. 0.5 C. 0.15 D. 0.05
A. 1.05
How do you construct the probability distribution of the random variable?
A. By getting the probability of occurrence of each value of the random variable.
B. By counting only the number of times an event occurred.
C. By establishing the frequency distribution of the values of the random variable.
D. By determining whether the data is a parameter or a statistic.
A. By getting the probability of occurrence of each value of the random variable.
How many ways can a "double" come out when you roll two dice?
A. 2 B. 4 C. 6 D. 8
C. 6
A fair coin is tossed three times and the sequence of heads (H) and tails (T) is observed. What is the probability that no heads will appear?
A. 1/8 B. 3/8 C. 5/8 D. 2/3
A. 1/8
Which of the following refers to the central value or average of its corresponding probability mass function?
A. mean B. median C. mode D. variance
A. mean
Which of the following refers to the two values that describe how scattered or spread out the scores are from the mean value of the random variable?
A. mode and median
B. mode and variance
C. median and standard deviation
D. variance and standard deviation
D. variance and standard deviation
What is the first step in finding the variance of a discrete probability distribution?
A. Calculate the standard deviation
B. Find the mean of the probability distribution
C. Subtract the mean from each value of the random variable X
D. Multiply the square of the difference of X and the mean by each value of the random variable.
B. Find the mean of the probability distribution
Which statement is NOT true about the variance of a discrete random variable?
A. Variance is always nonnegative.
B. It tells the average of the items in a discrete probability distribution.
C. It measures how far apart the elements of the set are spread out.
D. High variance indicates that the data points are very spread out around the mean.
B. It tells the average of the items in a discrete probability distribution.
Which of the following denotes the standard normal distribution?
A. A B. X C. Y D. Z
D. Z
Which of the following is NOT a property of a standard normal distribution curve?
A. The total area under it is 1.
B. The curve is symmetric about the center.
C. It is divided into positive 2 and negative 2 standard deviations.
D. The mean, median, and mode have the same value and are located at the same point.
C. It is divided into positive 2 and negative 2 standard deviations.
According to the empirical rule, what is the area under the part of normal curve in the standard normal distribution that lies within 2 standard deviations of the mean?
A. 68% B. 95% C. 99.7% D. 100%
B. 95%
A set of Mathematics exam scores has a mean of 68 and a standard deviation of 8. A set of English exam scores has a mean of 75 and a standard deviation of 10. For which exam would a score of 78 have a higher standing?
A. Math B. English
C. both Math & English D. cannot be determined
A. Math
A random variable X has a mean of 4 and a standard deviation of 2. What is the corresponding z-score for x = 7?
1. 5
In a class of 40 students, the score at the 50th percentile is 85. Which of the following does this mean?
A. Half of the students scored above 85.
B. Half of the students scored below 85.
C. 85 is the highest score in the class.
D. The student with the score of 85 ranks at the top of the class.
B. Half of the students scored below 85.
Which of following is true about the mean of the sample means?
A. The mean of the sample mean is equal to the population mean.
B. The mean of the sample mean is equal to the population mean divided by the population variance.
C. The mean of the sample mean is equal to the square of population mean.
D. The mean of the sample mean is equal to the square root of population mean.
A. The mean of the sample mean is equal to the population mean.
Which concept of random sampling distribution of the sample means is using Central Limit Theorem?
A. If you have a population mean and standard deviation and take sufficiently large random samples from the population with replacement, then the distribution of the sample means will be approximately distributed normally.
B. The probability of the simultaneous occurrence of two events that are independent is given by the product of their individual probabilities.
C. If you have a population mean µ and standard deviation and take sufficiently large random samples from the population with replacement, then the distribution of the sample means will be approximately distributed same as the original population.
D. The larger the sample size n in sampling distribution of sample mean, the lesser the histogram is to show the normalcy of the distribution.
A. If you have a population mean and standard deviation and take sufficiently large random samples from the population with replacement, then the distribution of the sample means will be approximately distributed normally.