Question 1

Which of the following refers to a function which assigns each sample point to a real number?

Accepted Answer

random variable

Answer

corresponding variable

Answer

discrete variable

Answer

continuous variable

Question 2

Which of the following is NOT a continuous variable?

Accepted Answer

number of riders who deliver pizza within Marikina

Answer

time allotted by an individual in jogging at Marikina Sport Center

Answer

volume of rainwater in Marikina River

Answer

height of basketball players in Marikina

Question 3

Which of the following best describe/s a discrete variable?

I. It is always a whole number.

II. It is obtained through counting.

III. It is obtained through measuring.

Accepted Answer

I and II only

Answer

I and III only

Answer

I only

Answer

II and III only

Question 4

Suppose a team of two members is to be formed from a group with one male and three females. If X is a random variable for the number of males in the team formed, what are the possible values of X?

Accepted Answer

{0,1}

Answer

{1}

Answer

{0}

Answer

{1,2}

Question 5

Suppose a team with two members is to be formed from a group consisting of one male and three females. What is the probability that a team with two members has one female member?

Accepted Answer

50%

Answer

25%

Answer

45%

Answer

20%

Question 6

The mean of a random variable X is also known as the _________________.

Accepted Answer

expected value

Answer

population mean

Answer

sample mean

Answer

margin of error

Question 7

Which of the following describes the process of finding the mean of a random variable X?

Accepted Answer

Multiply the values of X to the corresponding probability, then add.

Answer

Multiply the probabilities then add to the sum of the values of X.

Answer

Add the values of X to the corresponding probability, then multiply.

Answer

Add all the probabilities of the values of X then multiply to each value.

Question 8

What is the probability that there is at least one defective battery?

Accepted Answer

50%

Answer

10%

Answer

30%

Answer

20%

Question 9

What is the mean of the random variable X?

Accepted Answer

0.9

Answer

0.5

Answer

0.7

Answer

0.3

Question 10

What is the variance of the random variable X?

Accepted Answer

1.09

Answer

1.00

Answer

2.71

Answer

0.99

Question 11

Which of the following DOES NOT describe a normal probability distribution?

Accepted Answer

The total area under the normal curve is equal to 100.

Answer

The mean, median and mode are equal.

Answer

The curve is asymptotic to the horizontal axis.

Answer

The curve is symmetric with respect to the population mean.

Question 12

In which of the following intervals is where the middle 95% of a normal distribution found?

Accepted Answer

within μ – 2σ and μ + 2σ

Answer

within μ – 1/2σ and μ + 1/2σ

Answer

within μ – 3σ and μ + 3σ

Answer

within μ – σ and μ + σ

Question 13

What is the area of the shaded region shown below?

Accepted Answer

0.1131

Answer

0.9061

Answer

0.8829

Answer

0.8869

Question 14

Which of the following is the error in Paowee's solution?

Accepted Answer

The population standard deviation should be 1.58

Answer

The mean is 2.5 and not 23.5.

Answer

The numerator should be μ – X.

Answer

He used a lowercase letter x for the data point.

Question 15

What should be the value of z?

Accepted Answer

0.32

Answer

-0.20

Answer

-0.31

Answer

0.23

Question 16

It was observed that the average height of Marikeños is 65 inches with a standard deviation of3.5 inches. Assume the random variable X which represents the heights collected follows a normal distribution.

What is P(X =65)?

Accepted Answer

0%

Answer

25%

Answer

50%

Answer

75%

Question 17

It was observed that the average height of Marikeños is 65 inches with a standard deviation of3.5 inches. Assume the random variable X which represents the heights collected follows a normal distribution.

What is P(X =65)?

What percent of the population has height between 61.5 inches and 68.5 inches?

Accepted Answer

68%

Answer

99.7%

Answer

95%

Answer

50%

Question 18

It was observed that the average height of Marikeños is 65 inches with a standard deviation of3.5 inches. Assume the random variable X which represents the heights collected follows a normal distribution.

What is P(X =65)?

What z-score corresponds to 67 inches?

Accepted Answer

0.57

Answer

0.72

Answer

0.75

Answer

0.87

Question 19

It was observed that the average height of Marikeños is 65 inches with a standard deviation of3.5 inches. Assume the random variable X which represents the heights collected follows a normal distribution.

What is P(X =65)?

What percentage of Marikeños fall shorter than 67 inches?

Accepted Answer

71.57%

Answer

21.57%

Answer

57.14%

Answer

82.75%

Question 20

It was observed that the average height of Marikeños is 65 inches with a standard deviation of3.5 inches. Assume the random variable X which represents the heights collected follows a normal distribution.

What is P(X =65)?

If there are 420,000 Marikenos, how many have heights that are equal to67 inches or higher?

Accepted Answer

119,406

Answer

180,120

Answer

180,012

Answer

119,460

Question 21

Which of the following refers to the process of selecting a portion of the population such that each member has equal chance of being selected?

Accepted Answer

random sampling

Answer

statistic

Answer

sampling

Answer

parameter

Question 22

Which of the following is a parameter?

Accepted Answer

Answer

Answer

Answer

<math>\overline{\mathrm{X}}</math>

Question 23

Which of the following is true about a statistic?

I. It is obtained from the entire population.

II. It describes the sample and labels the population.

III. It can be used to make an inference about the population.

Accepted Answer

II and III only

Answer

I and III only

Answer

I, II and III

Answer

I and II only

Question 24

Consider the sample 3, 6, 7, 5, 5. Which of the following statements is INCORRECT?

Accepted Answer

The sample mean is 5.2 and it is a parameter.

Answer

The median score is 5 and it is a statistic.

Answer

The standard deviation is 1.48 and it is a statistic.

Answer

The sample size is 5 and it is a statistic.

Question 25

Which of the following is NOT TRUE about the standard error of sample means?

Accepted Answer

As the sample size increases, the standard error also increases.

Answer

It is the standard deviation of the sample means.

Answer

A small standard error means that the sample means are close to each other.

Answer

As the sample size decreases, the standard error increases.

Question 26

Based on the table below, what is the value of k?

Accepted Answer

0.3

Answer

0.4

Answer

1.0

Answer

0.5

Question 27

Based on the table below, what is E( $\overline{\mathrm{X}}$ )?

Accepted Answer

3.1

Answer

3.6

Answer

2.8

Answer

2.5

Question 28

What is _{$\sigma_{\overline{\mathrm{X}}}$ ?}

Accepted Answer

0.70

Answer

1.76

Answer

1.33

Answer

0.49

Question 29

Moira is going to Marikina Public Market. Her wallet has PhP 20, PhP 50and PhP 100 bills. If she will randomly select two bills, which of the following is NOT the mean of the chosen bills?

Accepted Answer

PhP 50

Answer

PhP 35

Answer

PhP 60

Answer

PhP 75

Question 30

If Moira will randomly choose two bills, which of the following may be done to find the mean of the sample means?

I. Add the amounts of the bills she has, then divide by three.

II. Get the means of all samples of size two, then add these means divided by three.

Accepted Answer

either I or II

Answer

neither I nor II

Answer

II only

Answer

I only

Question 31

Which if the following correctly states the Central Limit Theorem?

Accepted Answer

As the sample size increases, the sampling distribution approximates a normal distribution.

Answer

As the sample size increases, the mean of the sample become larger than the mean of the population.

Answer

As the sample size increases, there is lesser probability of committing erroneous inference about a population.

Answer

As the samples size increases, the statistic becomes closer to the parameter.

Question 32

Which of the following is the formula in finding the standard error when sampling is done with replacement or when the population is ‘infinite’?

Accepted Answer

<math>\sigma_{\overline{\mathrm{X}}}=\frac{\sigma}{\sqrt{n}}</math>

Answer

<math>\sigma=\frac{\sigma_{\overline{\mathrm{X}}}}{\sqrt{n}}\left(\sqrt{\frac{N-n}{N-1}}\right)</math>

Answer

<math>\sigma_{\overline{\mathrm{X}}}=\frac{\sigma}{\sqrt{n}}\left(\sqrt{\frac{N-n}{N-1}}\right)</math>

Answer

<math>\sigma=\frac{\sigma_{\overline{\mathrm{X}}}}{\sqrt{n}}</math>

Question 33

Based on observation, the average speed of Montalban jeepney drivers is 56 kph with population standard deviation of 3.5 kph. Assume that the driving speeds of these drivers follow a normal distribution.

If samples of size 10 were randomly chosen, what is the standard error?

If samples of size 10 were randomly chosen, what is the mean of the sample means?

Accepted Answer

56 kph

Answer

46 kph

Answer

5.6 kph

Answer

3.5 kph

Question 34

Based on observation, the average speed of Montalban jeepney drivers is 56 kph with population standard deviation of 3.5 kph. Assume that the driving speeds of these drivers follow a normal distribution.

If samples of size 10 were randomly chosen, what is the standard error?

Accepted Answer

1.11 kph

Answer

1.16 kph

Answer

2.21 kph

Answer

2.36 kph

Question 35

Based on observation, the average speed of Montalban jeepney drivers is 56 kph with population standard deviation of 3.5 kph. Assume that the driving speeds of these drivers follow a normal distribution.

If samples of size 10 were randomly chosen, what is the standard error?

What is the probability that if 10 jeepney drivers were randomly chosen, their average speed would be greater than 58 kph?

Accepted Answer

3.51%

Answer

96.41%

Answer

3.59%

Answer

96.49%

Question 36

Which of the following refers to the range of values which is assumed to contain the unknown parameter?

Accepted Answer

confidence interval

Answer

level of significance

Answer

point estimate

Answer

level of confidence

Question 37

Based on a set of data with 70 values, the mean depth of Marikina River during typhoons is 17.8 meters. The population standard deviation of the depths of Marikina River during typhoons is 3.8 meters. Assume that the depth of Marikina River follows a normal distribution.

What is the margin of error at 90% confidence level?

Accepted Answer

0.75

Answer

0.67

Answer

0.72

Answer

0.89

Question 38

Based on a set of data with 70 values, the mean depth of Marikina River during typhoons is 17.8 meters. The population standard deviation of the depths of Marikina River during typhoons is 3.8 meters. Assume that the depth of Marikina River follows a normal distribution.

What is the margin of error at 90% confidence level?

What is the confidence interval at 90% confidence level?

Accepted Answer

[17.05 m, 18.55 m]

Answer

[15.25 m, 19.75 m]

Answer

[16.91m, 18.69 m]

Answer

[16.23 m, 18.88 m]

Question 39

Which part of Kendra’s shows the first error she committed?

Accepted Answer

II

Answer

I

Answer

IV

Answer

III

Question 40

What is the reason behind the identified error?

Accepted Answer

She used the z-value for 95% level of confidence.

Answer

She subtracted the margin of error incorrectly.

Answer

She used t-value instead of z-value.

Answer

She rounded of the square root of 15 wrongly.

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