此题为判断题(对,错)。
此题为判断题(对,错)。
B.They both need a sampling frame of each of the subgroups of the target population.
C.In both of them,researchers want to ensure that all strata are included in the sample in order to enhance the representativeness of the sample and/or to enable comparisons between strA
D.Stratified sampling does not need a sampling frame to generate a stratified sampl
E.
E.In both of them,once the sample number of each subgroup is defined,samples are drawn in simple random sampling or systematic sampling metho
D.
B.A sampling method which involves having a constant sampling interval, the starting point for testing is determined randomly.
C.A sampling method in which the auditor selects a block of contiguous items from within the population.
D.Testing items with a certain characteristiC.
1. With regard to the sampling, there were a limited number of students in the 15- to 18-year age range because fewer referrals of this age group were made to sleep centers and psychologists. There were a limited number of participants from the hospital samples who were diagnosed with ARC, DSPS, or RLS in this initial study, necessitating further validation studies with larger sample sizes. Furthermore, the recent changes in diagnostic criteria for OSAS and PLMD in children require further validation studies with larger sample sizes using these new hospital diagnostic criteria.
A、Revisiting previous sections or key results
B、Relating the study results to those of existing research
C、Specifying Achievements/Contributions & Implications
D、Identifying Limitations/ Suggesting Future work & Applications
A、The shorter the sampling interval, the better
B、The sampling frequency must be greater than or equal to the maximum freqeuncy times two
C、It is not neccesary that the sampled signal contains all the information of the continuous-time signal
D、Discretization in the time domain corresponds to periodization in the frequency domain
A compact disk (CD) is used to store music. Suppose that both the two independent channels of the true stereo music with the highest frequency 22.05 kHz are sampled at the Nyquist sampling rate, then the sampling rate for each channel is f (kHz). The encoded PCM is to have an average SNR of at least 96 dB. Then, the minimum number of the uniform quantization of the sampled data should be R bits. If the Beethoven's Symphony No. 9 with 74 minutes in PCM data can be stored in CD, the minimum storage capacity of the CD should be T (MB, Megabyte). (Hint:).
A、f=44.1, R=16, T=783
B、f=22.05, R=16, T=392
C、f=44.1, R=15, T=700
D、f=44.1, R=16, T=392
A real estate company is interested in testing whether, on average, families in Gotham have been living in their current homes for less time than the families in Metropolis have. A random sample of 100 families from Gotham and a random sample of 150 families in Metropolis yield the following data on length of residence in current homes: Gotham:months,; Metropolis:months,. what is the standardized value of the estimate of the mean of the sampling distribution of the difference between sample means?
A、– 8.75
B、– 3.69
C、– 2.33
D、– 1.96
A、Simple random sampling
B、Systematic sampling
C、Stratified sampling
D、All of the above are methods of probability sampling.
B.population variance is smaller than the sampling distribution varianc
E.
C.population variance is larger than the sampling distribution varianc
E.
D.variances have the same degrees of freedom.
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