1. the ____ equal zero if two random variable say X and Y are independent a) cov
ID: 3182789 • Letter: 1
Question
1. the ____ equal zero if two random variable say X and Y are independent
a) covariance
b) mean
c) correlation coefficient
d) standard devitation
2. A __ is ramdom variable whose valus can be calculated from sample data
a) statistic
b) parameter
c) distribution
d) condition probability
3. * Random Sample of size 75 were selected from a population with a mean of 56 and a variance of 12. what are the mean and standard deviation of sampleing distribution of the sample mean. please explain step by step
4. A___ sample is a sample in which all the Xs are independent ramdom variable and every x has the sample probability distribution
a) continuous
b) discrete
c) random
d) normal
5. which of the following is not a correct statement with regard to usign the normal distrobuiton to approximate a binomial probability distribution
a) the normal approximation can be used to provided n is suddiciently large the trials are independent and P(s) is constant from trial to trial
b) when p closed to 0.5 then each of x have a distribution that approximate symmetric
c) when p is closed to 0 or 1 then each of the x have a skewed distribution and the normal approximation should never be used
d) a normal approximation is appropriate when the values of np and n(1-p) both equal or exceed 10
6. for a raomdon sample of size n, the central limit theorem state if n is sufficiently large then the sample mean and the sample total to
a) appricimately normally distrubuted
b) have standard devitation that are normally distributed
c) have flat or uniform distribution
d) have a skewrd distribution
Explanation / Answer
1. covariance is given by cov (x,y) = E[ xy ] - E[x] E[y]; if two events are independent then E[ xy ] = E[x] E[y].
covariance equals zero if 2 events are independent.
2.Parameters are numbers that summarize data for an entire population. Statistics are numbers that summarize data from a sample, i.e. some subset of the entire population.
statistic is the answer
3.given n = 75; sample mean = population mean = 56; sample standard deviation = standard deviation / sqrt(n) = 2/5 = 0.4;
4.Random sample is a sample where all X are independent random variables.
5. the below option is not correct and the rest all are right
the normal approximation can be used to provided n is suddiciently large the trials are independent and P(s) is constant from trial to trial
6. The Central Limit Theorem states that if the sample size, n, is sufficiently large, the sampling distribution of the means will be approximately normal no matter whether the population is normally distributed, skewed, or uniform.
option A is right
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.