Statistics and Probability Answers

Which option consists of correct data collection methods?

Select one:

a. Experiments and organised data

b. Intervals, observations and secondary data

c. Surveys, interviews and questionnaires

d. Interviews, primary data and observations

Identify the appropriate measure of central tendency that can be used to find the average speed of a journey.

Select one:

a. Mode

b. Weighted mean

c. Harmonic mean

d. Geometric mean

Students divided into different groups according to their intelligence and gender. This is an example of____.

Select one:

a. constant data

b. quantitative data

c. continuous data

d. qualitative data

Identify the CORRECT statement about inferential statistics.

Select one:

a. Inferential statistics deals with methods of organizing, summarizing, and presenting data in a convenient and informative way.

b. In inferential statistics, we study the methods to make decisions about population based on sample results.

c. In inferential statistics, we study how a sample is obtained from a population.

d. In inferential statistics, we study how to make decisions about mean, median, or mode.

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__________ is found by adding up all the data values and then dividing the total by the sample size.

Select one:

a. Mode

b. Median

c. Average

d. Central location

In a Least Square Regression line the quantity is always________.

Select one:

a. positive

b. zero

c. fractional

d. negative

B. Directions: Read and understand each problem carefully. In each of the following problems:

1. state the null and alternative hypothesis;

2. compute the test statistics value of population proportion;

3. determine the critical value and the rejection region; and

4. draw a conclusion.

2. It is claimed that last year, 65% of the people believed that there was an improvement in the country’s economy. Suppose this year, only 270 out of 450 people randomly selected believe that there is an improvement in the country’s economy. Does this indicate that there is a decrease in the number of people who believed that there is an improvement in the country’s economy? Use 0.05 significance level.

B. Directions: Read and understand each problem carefully. In each of the following problems:

1. state the null and alternative hypothesis;

2. compute the test statistics value of population proportion;

3. determine the critical value and the rejection region; and

4. draw a conclusion.

1. A research conducted in a certain company last year showed that 25% of the employees would rather drink coffee than soft drinks during break time. The company has recently divided to give free coffee during break time. In the new research conducted this year, out of the 125 randomly sampled employees 28% said that they would rather drink coffee than soft drinks. At 0.05 level of significance, is there sufficient evidence to suggest that the coffee drinkers have increased since the company has decided to give free coffee during break time? 

A. Direction: Find the sample proportion. (Show your complete solution.)

1. n = 550, x = 308

2. n = 480, x = 168

3. n = 620, x = 248

4. n = 740, x = 259

5. n = 1,120, x = 616