A survey is conducted to determine the most common reason people own a cell phone. A company sent out a survey to customers between the ages of 20 and 30. Based on the responses, the company concluded that people own a cell phone for messaging purposes. Is this conclusion valid?(1 point)
Responses
Yes, because the sample includes all customers between the ages of 20 and 30.
Yes, because the sample includes all customers between the ages of 20 and 30.
Yes, because the sample includes male and female customers.
Yes, because the sample includes male and female customers.
No, because not all people who own a cell phone have the same probability of being selected.
No, because not all people who own a cell phone have the same probability of being selected.
No, because the sample includes customers of too many different ages.
No, because the sample includes customers of too many different ages.
No, the conclusion is not valid based only on the responses from customers between the ages of 20 and 30. The sample may not be representative of the entire population of cell phone users, and there may be other reasons why people own cell phones, such as for making calls, accessing the internet, or using specific apps.
A school principal wants to know the average number of extracurricular activities students in her school are involved in. She assigned each student a number from 1 to 415. Using a random number generator, she selected 200 students to be part of the sample. She concluded that students are involved in an average of two extracurricular activities. Is the principal’s conclusion valid?(1 point)
Responses
Yes, because every student had an equal chance to be part of the sample. The sample size also appears to be large enough.
Yes, because every student had an equal chance to be part of the sample. The sample size also appears to be large enough.
Yes, because only those who have extracurricular activities were included in the sample.
Yes, because only those who have extracurricular activities were included in the sample.
No, because not all students in the sample have extracurricular activities.
No, because not all students in the sample have extracurricular activities.
No, because 200 students in the sample is too large.
No, the principal’s conclusion is not valid based on the given information. The sample size appears to be large enough and each student had an equal chance to be part of the sample, but the principal’s conclusion assumes that every student in the sample is involved in extracurricular activities, which may not be true. The principal would need to confirm that each selected student is actually involved in at least one extracurricular activity.
In a random sample of 400 watches, 3 are defective. Out of a total of 10,500 watches, how many would you expect to be defective based on this sample data?(1 point)
We can use proportions to solve this problem.
The proportion of defective watches in the sample is:
3/400
We can use this proportion to estimate the number of defective watches in the total population:
(3/400) = x/10,500
Simplifying and solving for x:
x = (3/400) * 10,500 = 78.75
Therefore, based on this sample data, we would expect approximately 78.75 watches out of 10,500 to be defective. Since we cannot have a fractional amount of defective watches, we can round this up to 79.
Answer: We would expect 79 watches out of 10,500 to be defective based on this sample data.
A store manager wants to know the percentage of shoppers who use coupons. He surveys everyone who enters the meat aisle. He finds that 60 percent of shoppers use coupons. Does the sampling method the store manager used support a valid inference?(1 point)
Yes, because the manager asked everyone who entered the meat aisle.
Yes, because the manager asked everyone who entered the meat aisle.
No, because the sample is not chosen randomly.
No, because the sample is not chosen randomly.
No, because not all people who enter the meat aisle use coupons.
No, because not all people who enter the meat aisle use coupons.
Yes, because the sample contains coupon users and non-users.
Yes, because the sample contains coupon users and non-users.
No, the sampling method the store manager used does not support a valid inference. The manager only surveyed shoppers who entered the meat aisle, which may not be representative of the entire population of shoppers in the store. Additionally, not all people who enter the meat aisle use coupons, so the sample may not accurately reflect the percentage of shoppers who use coupons in the entire store. A random sampling method would be more appropriate for making a valid inference about the percentage of shoppers who use coupons.
A quality control manager wants to determine the percentage of defective light bulbs in the production line. Which of the following sampling methods would most likely lead to a valid inference?(1 point)
Responses
testing the first 2,000 light bulbs in the production line
testing the first 2,000 light bulbs in the production line
testing every fiftieth light bulb in the production line
testing every fiftieth light bulb in the production line
testing the last 4,000 bulbs in the production line
testing the last 4,000 bulbs in the production line
retesting 100 light bulbs that have already been tested
The correct answer is No, because not all people who own a cell phone have the same probability of being selected.
Explanation: The conclusion is not valid because the sample only includes customers between the ages of 20 and 30. This means that the survey did not consider people who are younger than 20 or older than 30, who may have different reasons for owning a cell phone. Additionally, the survey may not have included a representative sample of the entire population of cell phone owners. Therefore, the conclusion cannot be generalized to all cell phone owners.