Statıstıcs I

Yanıt Açıklaması: The advantages of the data collection by interview are: 1. People will tend to give answers to the question when they are approached in person or by telephone, so the data collection by interview usually includes usable information from those people who are conducted. 2. Direct contact with the responders avoids misunderstanding of the questions. On the other hand, the limitations of the interviewing method are: If the questioner does not obey the rules for selecting individuals or may select an irrelevant individual about the study, this leads to bias into the results. The questioner may affect the individuals’ opinion about a question and this leads to get incorrect answers. The questioner may make recording errors.

Yanıt Açıklaması: 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.

Yanıt Açıklaması: 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

Yanıt Açıklaması: Statistics is at the heart of understanding climate patterns and making weather forecasts. The first role of Statistics is to reduce this mass of complex data to a simpler form in order to facilitate understanding and learning from the data. This is often done by making graphical representations of the data.

Yanıt Açıklaması: 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.

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

Yanıt Açıklaması: 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.

Yanıt Açıklaması: 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.

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

Yanıt Açıklaması: 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.

Yanıt Açıklaması: 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.

Yanıt Açıklaması: It may seem that everything may be recorded and stored somewhere. But in reality - unless we somehow centralize and link all the databases in the world, and have free access to them - we can get access to only a small part of whatever data we are interested in. For example, it is impossible to ask the whole population of Turkey what their view on climate change is, whether they believe it is natural or manmade. This is where the most basic concept in Statistics comes into play: sampling from a population.

Yanıt Açıklaması: qualitative ordinal. pg. 14. Correct answer is C.

Yanıt Açıklaması: 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

Yanıt Açıklaması: A pie chart usually does not show the actual values, therefore, it may easily become a misleading chart.

Yanıt Açıklaması: 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.

Yanıt Açıklaması: 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.

Yanıt Açıklaması: qualitative nominal

Yanıt Açıklaması: 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.

Yanıt Açıklaması: 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.