Statıstıcs I Ara 1. Deneme Sınavı

The paragraph is an example of experimental design in sports science. So, drinking coffee and water on pre-trainings appears to be beneficial to athletes. More experiments with more athletes should be undertaken in other conditions and controls.

The data is already ordered. There are 10 observations:

(10+1)/2 = 5.5

so the median is the arithmetic mean of 5th and 6th observations:

median =(5 +6)/2=5.5

The subjects or individuals or companies on which these observations are made are called cases. Hospital patients on whom we have measured the standard medical indicators such as blood pressure, cholesterol levels, blood sugar, and so on might be cases.

When the data set is large or the measurements are obtained using ratio scale, grouped frequency is more appropriate for summarizing the data.

Ordinal scales of measurement have the property of both classifying and magnitude. Subjects are categorized into different rank ordered groups. Each value on the ordinal scale has a unique meaning, and it has an ordered relationship to every other value on the scale.

The main criteria for selecting a sample will be that the sample is representative of the population and that there’s no or very little subjectivity in the choice of the sampling units.

The mode is the main centrality measure for nominal scales. The correct answer is A.

Big Data are all forms of data we have obtained from different sources and transformed into meaningful and workable forms. All data that are very large numbers, every value in the billions and trillions do not constitute "big data" because cannot be transformed into meaningful and workable forms. 

A reasonable survey would carefully select people as a sample and gathering data from Denizli would not represent Turkey. Statistics working on samples cannot give absolutely correct information. Sample being carefully selected, it can give a statistical estimate of proportions.

qualitative ordinal. pg. 14. Correct answer is C.

The weighted average score is calculated by multiplying the weight of an exam and the score taken in that exam. Thus the scores of students are calculated as follows:

Ahmet: (40*0.4)+(80*0.6)=64

Mehmet: (80*0.4)+(60*0.6)=68

Ali: (40*0.4)+(90*0.6)=74

Asya: (70*0.4)+(90*0.6)=82

Suzan: (40*0.4)+(60*0.6)=52

Then the average score of the group is equal to (64+68+74+82+52)/5=68

In order to find the median of this raw data, first, let’s order the data from smallest to largest as follows 3,3,4,5,6,6,6,7

The location of the median in this ordered data is (8+1)/2 = 4,5th observation. Therefore, we
need to identify the 4th and 5th observations’ values in the ordered data, these are 5 and 6 respectively.

The Median is equal to (5+6)/2 = 5,5

The answer is B.

A frequency distribution table provides information of how many observation or elements occurred for each value or group of values of a variable. Cumulative frequency is used to determine the number of elements that falls above or below a particular value in a given class interval.

qualitative nominal

The easiest form of data is called categorical, or qualitative, for example data on variables “country” (e.g., the data observation might be Germany) or “question response” (e.g., believe that climate change is manmade) or “exam grade” (e.g., B). Categorical variables and data can be either nominal or ordinal. The question about climate change, with possible responses “natural”, “manmade” or “don’t know/can’t answer” is a nominal categorical variable, as is the variable “country” - there is no ordering in the categories of these variables. By contrast, exam grade is an ordinal categorical variable, since its categories are ordered: A is better than a B, B is better than a C, and so on.

Other examples of nominal categorical variables are gender, region of residence, field of study, type of transport, type of housing, etc.

Other examples of ordinal categorical variables are income group (if incomes have been categorized), an attitude question in a survey where possible responses are strongly agree/agree/disagree/strongly disagree (these categories have an order), social class (with classes usually in an inherent order), terrorist threat levels (in the UK these are low/moderate/substantial/severe/critical), etc.

As also understood from the information given, “Region of Residence”, “Field of Study”, “Type of Transport” and  “Type of Housing” are nominal categorical variables, so the correct answer is D. Exam grade (either A, B, or C, etc) is ordinal categorical variable.

A properly created graph can report various information of the data in a visual form. For instance, the shape of the distribution of the data, the relation between two sets of data, the most repeating observations, outliers, peaks, summary statistics (minimum, maximum, range, mean, median) etc. can be identified from graphics.