Stats Chapter 1 section 3 & 4
How do you find K with systematic sampling?
Take N the overall population and divide that by desired sample amount Ex: 7149 (N) / 60 (n) = 119 (always make sure to round k down
A salesperson obtained a systematic sample of size 30 from a list of 750 clients. To do so, he randomly selected a number from 1 to 25, obtaining the number 18. He included in the sample the 18th client on the list and every 25th client thereafter. List the numbers that correspond to the 30 clients selected. Choose the correct answer below. A 18, 43, ..., 738 B.30, 55, ..., 750 C.18, 43, ..., 743 D.25, 43, ..., 547
To find answer must do p, p+(n-1)K 18+ (30-1)25 = C. 18, 43,..., 743
Determine whether the following statement is true or false. Explain. When conducting a cluster sample, it is better to have fewer clusters with more individuals when the clusters are heterogeneous.
True, because when the clusters are heterogeneous, they are scaled down versions of the population.
A radio station asks its listeners to call in their opinion regarding the format of the morning show. What type of sampling is used? A.Convenience B.Systematic C.Stratified D.Cluster E.Simple random
Convenience sample
Which sampling method does not require a frame? A. Simple random B. Systematic C. Cluster D. Stratified E. All of the above sampling methods require a frame
B. Systematic Sampling does not require a frame
To determine customer opinion of their musical variety, Sony randomly selects 70 concerts during a certain week and surveys all concert goers. What type of sampling is used? A.Stratified B.Convenience C.Cluster D.Simple random E.Systematic
Cluster sampling
Determine whether the following statement is true or false. Explain. A simple random sample is always preferred because it obtains the same information as other sampling plans but requires a smaller sample size.
False, because other sampling techniques may provide more information for less cost than a simple random sample.
IBM wants to administer a satisfaction survey to its current customers. Using their customer database, the company randomly selects 40 customers and asks them about their level of satisfaction with the company. What type of sampling is used? A.Stratified B.Systematic C.Simple random D.Convenience E.Cluster
Simple random sampling
To determine her mood, Keri divides up her day into three parts: morning, afternoon, and evening. She then measures her mood at 3 randomly selected times during each part of the day. What type of sampling is used? A.Convenience B.Systematic C.Stratified D.Cluster E.Simple random
Stratified sample
What does it mean when sampling is done without replacement?
When sampling without replacement, once an individual is selected, the individual is removed from the possible choices for that sample and cannot be chosen again.
cluster sample
obtained by dividing the population into groups and selecting all individuals from within a random sample of the groups.
systematic sample
obtained by selecting every kth individual from the population. The first individual selected corresponds to a random number between 1 and k.
stratified sampling
obtained by separating the population into nonoverlapping groups called strata and then obtaining a simple random sample from each stratum. The individuals within each stratum should be homogeneous (or similar) in some way. In order for the stratified sample to be representative of the population, the number of individuals sampled from each stratum should be proportional to the size of the strata in the population. For example, if one wanted take a stratified sample of 100 individuals from a population that is 53% female and 47% male, then 53 females and 47 males should be sampled.
Random sampling
the process of using chance to select individuals from a population to be included in the sample
