Interval estimation : the population standard deviation is not known, the sample standard deviation is 50, there are 25 observations in the sample. What is the value of the standard error to calculate the confidence interval?

Which one of the following is also called availability sampling method?

Sample values for a continuous variable (water flow rate ; as liter / hour) : 6, 12, 17, 36, 26, 15, 34, and 2. What is the point estimate of the population arithmetic mean?

1. Formulate a decision rule

2. Identify the test statistic 

3.  State null and alternate hypotheses

4. Select a level of significance

5. Take a sample and make the decision

What is the correct order of the hypothesis testing steps given above? 

Population of statistics students is 500, population of statistics 201 course is 150 (40 are repeating only this), population of statistics 203 course is 160 (55 are repeating only this), population of statistics 305 course is 140 (35 are repeating only this). How many people are there in the target population for a survey about repeating 2nd year courses?

In a production line, the mean weight of the products should be 450 grams and the standard deviation of the weight variable is ? = 25. It is known that the distribution of the weights of the packages follow a normal distribution. A sample of 32 observations is randomly selected from the production line in the afternoon and the sample average is found as of 448 grams.The significance level ? = 0.05 for this problem.

If you follow the five step hypothesis testing procedure, what is the alternative hypothesis for the situation given above ? 

For ? = 0.24 significance level what is the acceptance area under the standard normal curve for two-sided tests?

Sample values for a continuous variable (rain drop rate ; as kg / hour) : 110, 125, 155, 130, 180, and 80. What is the point estimate of the population arithmetic mean?

In a two population hypothesis testing problem, population standard deviations are 40 and 30, sample sizes are 125 and 225 respectively. If the z value is calculated, what is the value of denominator for z?

There are 24 female ducks, 21 male ducks, 15 baby ducks, 27 female gooses, 18 male gooses, and 12 baby gooses in a farm. What is the population proportion estimate of babies in this farm?

In a classroom there are 25 students. Out of these 25 students 10 of them are male. If a hypothesis testing procedure for the population proportion of female students is to be created, what is the value of the sample proportion of the female students?

Interval estimation : the sample arithmetic mean is 14 and the lower limit of the confidence interval is 6, then what is the upper limit of the confidence interval?

A reseacher wants to analyse the consumption behaviors of people in a city. He divides the population into 4 groups: male/female and young/old. Then he estimates the proportion of each group in population and constructs the samples accordingly. So, which sampling method does he uses?

For sample one the sample size is 10, mean is 4.5, and standard deviation is 1. For sample two the sample size is 12, mean is 3.4, and standard deviation is 1.2 and (µ1 -µ2 ) is considered to be equal to 0. What is the test statistics for the given values? 

For ? = 0.567 significance level what is the rejection area under the standard normal curve for one-sided tests?

If there are 120 objects in a population and the investigator wants to use simple random sampling to choose objects in to a sample from this population, what is the probability of a object to be selected in to a sample?

If someone wants to carry out a research to find out the smoking rate in females over the age of 50 living in Eskişehir, what is the target population for this research? 

In an investigation, if the significance level is 0,01 ; what is the confidence level of this study ? 

Which is the first step to test the claims made about the population parameters?