Which of the following statistics are unbiased estimators of population parameters? choose the correct answer below. select all that apply. a. sample median used to estimate a population median. b. sample mean used to estimate a population mean. c. sample variance used to estimate a population variance. d. sample proportion used to estimate a population proportion. e. sample range used to estimate a population range. f. sample standard deviation used to estimate a population standard deviation.

B. Sample mean used to estimate a population mean.

C. Sample variance used to estimate a population variance.

D. Sample proportion used to estimate a population proportion.

Step-by-step explanation:

This is because the mean of the sampling distribution of the mean tends to target the population mean. Also, the mean of the sampling distribution of the variance tends to target the population variance.

This means that the sample mean and variance tend to target the population mean and variance, respectively, instead of systematically tending to underestimate or overestimate that value. This is why sample means and variances are good estimators of population means and variances, respectively. This is also true for proportions but not true for medians, ranges and standard deviations.

step-by-step explanation:

12: 00 p.m. to 7: 00 p.m. is a total of 7 hours.

4: 00 p.m. to 7: 00 p.m. is a total of 3 hours.

this means that from 4: 00 p.m to 7: 00 p.m. this represents 3/7 of what was lost from 12: 00 p.m. to 7: 00 p.m.

after knowing this, after doing 11,600 - 6,800 = 4,800

4,800 represents 3/7 of what was lost for 7 hours.

we then divide 4,800 by 3 which gets 1,600.

because we know that 1,600 represents 1/7 of how much water was lost, we just have to multiply by 7, which gets 11,200.   after adding 11,200 to how much water was left at 7: 00 p.m. which was 6,800. 11,200 + 6,800 = 18,000

this means that the pool originally had 18,000 gallons in the pool.

you can also check your work by doing 18,000 - 4(1600), which becomes           1800 - 6400 which gets you 11,600.

step-by-step explanation: