individual

Question

asked 2021-02-25

Give a full and correct answer
Why is it important that a sample be random and representative when conducting hypothesis testing?
Representative Sample vs. Random Sample: An Overview
Economists and researchers seek to reduce sampling bias to near negligible levels when employing statistical analysis. Three basic characteristics in a sample reduce the chances of sampling bias and allow economists to make more confident inferences about a general population from the results obtained from the sample analysis or study:
* Such samples must be representative of the chosen population studied.
* They must be randomly chosen, meaning that each member of the larger population has an equal chance of being chosen.
* They must be large enough so as not to skew the results. The optimal size of the sample group depends on the precise degree of confidence required for making an inference.
Representative sampling and random sampling are two techniques used to help ensure data is free of bias. These sampling techniques are not mutually exclusive and, in fact, they are often used in tandem to reduce the degree of sampling error in an analysis and allow for greater confidence in making statistical inferences from the sample in regard to the larger group.
Representative Sample
A representative sample is a group or set chosen from a larger statistical population or group of factors or instances that adequately replicates the larger group according to whatever characteristic or quality is under study.
A representative sample parallels key variables and characteristics of the large society under examination. Some examples include sex, age, education level, socioeconomic status (SES), or marital status. A larger sample size reduced sampling error and increases the likelihood that the sample accurately reflects the target population.
Random Sample
A random sample is a group or set chosen from a larger population or group of factors of instances in a random manner that allows for each member of the larger group to have an equal chance of being chosen. A random sample is meant to be an unbiased representation of the larger population. It is considered a fair way to select a sample from a larger population since every member of the population has an equal chance of getting selected.
Special Considerations:
People collecting samples need to ensure that bias is minimized. Representative sampling is one of the key methods of achieving this because such samples replicate as closely as possible elements of the larger population under study. This alone, however, is not enough to make the sampling bias negligible. Combining the random sampling technique with the representative sampling method reduces bias further because no specific member of the representative population has a greater chance of selection into the sample than any other.
Summarize this article in 250 words.

asked 2021-01-28

Data is being processed from 35 data sources. Each dataset may or may or net generate dataset at the beginning of each timeslot, the probability that any individual source actually generates a dataset is 0.004,and the data sources are independent. In each time slot we can process up to two datasets. Now, the processing is real time with the processed results only being considered if they are done within the time slot. Determine the probability that all incoming datasets can be processed in any particular time slot?

asked 2021-03-07

A hip joint replacement part is being stress-tested in a laboratory. The probability of successfully completing the test is 0.883. 11 randomly and independently chosen parts are tested. What is the probability that exactly two of the 11 parts successfully complete the test?

asked 2021-02-26

Census reports for a city indicate that 62% of residents classify themselves as Christian, 12% as Jewish , and 16% as members of other religions (Muslims, Buddhists, etc.).

The remaining residents classify themselves as nonreligious.

A polling organization seeking information about public opinions wants to be sure to talk with people holding a variety of religious views, and makes random phone calls. Among the first four people they call, what is the probability they reach a) all Christians? b) no Jews? c) at least one person who is nonreligious?

The remaining residents classify themselves as nonreligious.

A polling organization seeking information about public opinions wants to be sure to talk with people holding a variety of religious views, and makes random phone calls. Among the first four people they call, what is the probability they reach a) all Christians? b) no Jews? c) at least one person who is nonreligious?

asked 2021-02-02

Triangle XYZ undergoes a single
transformation to form the image,
triangle X′Y′Z′
. The image is congruent
to the original figure. Which of the
following best describes the possible
transformation that took place?

O A. a reflection only

O B. a rotation only

O C. a translation only

O D. a reflection, rotation, or a translation

O A. a reflection only

O B. a rotation only

O C. a translation only

O D. a reflection, rotation, or a translation

asked 2020-11-30

The spinner is spun twice. Two possible outcomes art AC and CA.

a. Create a sample space that lists all of the equally likely outcomes.

b. Refer to the sample space to find the probability of spinning A one or more times in two spins.

a. Create a sample space that lists all of the equally likely outcomes.

b. Refer to the sample space to find the probability of spinning A one or more times in two spins.

asked 2020-12-14

A card is drawn from a well-shuffled deck of 52 cards. Find the probability that the card is a black card or a 10

asked 2020-12-30

You are interested in finding a 95% confidence interval for the mean number of visits for physical therapy patients. The data below show the number of visits for 14 randomly selected physical therapy patients. Round answers to 3 decimal places where possible.

\(9 6 10 15 19 6 23 26 19 16 11 25 16 11\)

a. To compute the confidence interval use a t or z distribution.

b. With 95% confidence the population mean number of visits per physical therapy patient is between ___ and ___ visits.

c. If many groups of 14 randomly selected physical therapy patients are studied, then a different confidence interval would be produced from each group. About ___ percent of these confidence intervals will contain the true population mean number of visits per patient and about ___ percent will not contain the true population mean number of visits per patient.

\(9 6 10 15 19 6 23 26 19 16 11 25 16 11\)

a. To compute the confidence interval use a t or z distribution.

b. With 95% confidence the population mean number of visits per physical therapy patient is between ___ and ___ visits.

c. If many groups of 14 randomly selected physical therapy patients are studied, then a different confidence interval would be produced from each group. About ___ percent of these confidence intervals will contain the true population mean number of visits per patient and about ___ percent will not contain the true population mean number of visits per patient.

asked 2021-02-02

Determine whether the number described is a statistic or a parameter.

Of the students enrolled in a certain college, 80%, are full-time.

Of the students enrolled in a certain college, 80%, are full-time.

asked 2020-10-19

A manufacturer of digital phones has the following probability distribution for the number of defects per phone:
xf(x) .89 1.07 2.03 3.01

(a) Determine the probability of 2 or more defects. (b) Is a randomly selected phone more likely to have 0 defects or 1 or more defects?

(a) Determine the probability of 2 or more defects. (b) Is a randomly selected phone more likely to have 0 defects or 1 or more defects?