Deneme Sınavı Soruları

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? 

Which one of the following method's most important feature is efficiency?

The population variances for two samples are 2 and 5, the difference of the sample means for these two samples is 3, and the sample sizes are 100 and 500, respectively. For the given values what is the test statistic?

For two-sided test on one population hypothesis testing with α = 0.05 and n = 15, what is the degrees of freedom?

A scientist found the following statistics for a hypothesis testing of two population proportions:

Population 1 : x1=12, n1=60

Population 2 : x2=30, n2= 90

What is the observed t value in this problem? 

In an analysis of variance problem, if variance between samples is 45 and variance within samples is 125 then what is the F statistic?

Interval estimation : the limits of the confidence interval are (99, 123), the significance level is 0.01. What is the sample arithmetic mean?

Which of the following are among the reasons for sampling?

1. Cost
2. Time
3. Accuracy
4. Destructive tests
5. Esthetics

Sample values for a continuous variable are as follows (noise level of a laptop computer ; as decibel) : 16, 19, 23, 24, 27, 32, 17, and 10. What is the point estimate of the population arithmetic mean?

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?

I. Random numbers can be used to select simple random samples from a population frame. 

II. Each possible sample combination of the specified size does not have equal probability of being chosen. 

III. It is the most basic sampling method.

Which of the given is TRUE about simple random sampling?

I. Choose the level of significance α.

II. Determine the population proportion under study and form the null hypothesis (H0 ) and the alternative hypothesis (H1 ).

III. Identify the critical points and critical region for the hypothesis test.

IV. Calculate the test statistic z for proportions.

V. Based on sample information decide to reject or fail to reject the null hypothesis (H0 ) and interpret the results of the hypothesis test.

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

If a research team have a suspicion that sampling may lead to a bias, which sampling method is most likely the one used in the study?

A researcher wants to compute the mean weight of a certain product produced by a firm. The firm produces 8000 products per day and each product has a serial number from 1 to 8000. The researcher decide to choose 80 products in order to compute average weight. He chooses the products with serial numbers 3, 103, 203,303, 403, 503......7903. Which method of sampling did the researcher apllied?

In a problem, the population arithmetic mean is estimated via interval estimation, after some calculations, the sample mean is found as 45 and the lower limit of the interval is 40, therefore what is the upper limit of the interval estimate of the population arithmetic mean?

What is the shaded region indicated by arrows called in hypothesis testing?

I. Rejecting the null hypothesis in an ANOVA test means at least one of the means of the
population under consideration is different from the other population means. 

II. To compare two means through hypothesis testing procedure which is called one-way analysis of variance (one-way ANOVA) technique used to compare the means of two populations. 

III.  Rejecting the alternative hypothesis in an ANOVA test means at least one of the means of the population under consideration is different from the other population means. 

Which of the given statements about ANOVA test can said to be true?

I. The mean, median and mode of the t distribution are all equal to zero.

II. The t distribution is bell-shaped and symmetrical. The total area under a t-curve is 1 or  100%

III. As the degrees of freedom decreases, the shape of the t-distribution approaches to the standard normal distribution.

Which of the given statements about properties of the t-distribution are true?

Sample values for a continuous variable (weather temperature in a day ; as ^oC) : 10, 16, 20, and 28. What is the point estimate of the population arithmetic mean?