Statıstıcs I

Yanıt Açıklaması: In order to avoid the disadvantages and misleading of the range and the IQR, we need a measure of variability that is based on including all measurements in a data set. The most important and widely used measure of variability in statistics is the standard deviation. To determine the variation of a data set in terms of the amounts, we need to measure the how much each observation deviates from the mean. The variability of a data set is small if the observations are close to their mean, and large if the observations are deviated widely about their mean. The correct answer is C.

Yanıt Açıklaması: The probability distribution of a discrete random variable is a list of odds associated with each of its possible values. It is also called the probability function or the probability mass function. Basically we can define probability function as a rule that assigns probabilities to the values of random variables.

Yanıt Açıklaması: Probability of an Event = The number of times the event can happen / Total number of possible outcomes P (more than 3) = 3 / 6 = 0,5

Yanıt Açıklaması: Normal distribution is one of the most significant and extensively used continuous probability distribution. The major reason for this circumstance is majority of the continuous random variables which are observed through real life applications (social, medical, physical, biological) are normally or approximately normally distributed (bell-shaped) variables.

Yanıt Açıklaması: Each trial has only two possible outcomes, such as head and tail, 0 and 1 or success and failure.

Yanıt Açıklaması: This probability is called Hypergeometric distribution.The correct answer is A.

Yanıt Açıklaması: Discrete random variables have only a countable number of separate values such as 0, 1, 2 , 3... etc. For example, the number of students in a class for certain day or the number of customers in a supermarket after 5:00 PM are cases for discrete random variables since these variables are finite and countable. Conversely, continuous random variable can take entire infinite values in a given interval. Because of this reason, continuous random variables are commonly measured instead of counted. For instance, waiting time for customers in a supermarket cashier line and travel time of a bus between two points are examples for continuous random variables. The correct answer is C.

Yanıt Açıklaması: R = Largest Value - Smallest Value 20-10=10

Yanıt Açıklaması: z = (x – m) / sd ; sd = variance 1/2 ; (30 – 25) / 4 = 1.25 ; (35 – 25) / 4 = 2.5 ; P(1.25 <= z <= 2.5). pg. 200. Correct answer is E.

Yanıt Açıklaması: X =3+5+!+8=53= 5.3 A 10 10

Yanıt Açıklaması: The range of a data set, shown as R, is the difference between the largest and smallest values and calculated as follows: R = Largest Value - Smallest Value

Yanıt Açıklaması: Consider any two experiments of which the first experiment can result in n 1 and the second can result in n 2 possible outcomes. Then, considering both experiments together, there are n 1 n 2 possible outcomes. P=20x5=100

Yanıt Açıklaması: Simple bar chart is used to represent discrete values for each category for a given variable on x-axis (horizontal).

Yanıt Açıklaması: 14 : occurs most often, it is repeated 5 times. pg. 77. Correct answer is A.

Yanıt Açıklaması: number of university students in Eskişehir. pg. 179. Correct answer is B.

Yanıt Açıklaması: There are different possible outcomes and the sample space is S = {X1X2, Y1Y2, Y1Y3, Y2Y3, X1Y1, X1Y2, X1Y3, X2Y1, X2Y2, X2Y3} If the event “one brand X and one brand Y phone is chosen” is denoted by E, the elements of E are . E = { X1Y1, X1Y2, X1Y3, X2Y1, X2Y2, X2Y3} The probability that event E will occur. P(E)=n(E):n(S) = 6:10 =0.6

Yanıt Açıklaması: In the classical probability approach to assign a probability to an event, the assumption is that all the outcomes have the same chance of happening. Pick up a six-sided fair die, there are six numbers on each face of the die as 1, 2, 3, 4, 5, and 6. Classical probability says that each side of the die has the same chance to come face up if this die is thrown. Since there are 6 possible outcomes of throwing a six-sided fair die probability of obtaining any number represented on the faces of this six-sided fair die is 1/6.

Yanıt Açıklaması: We have to compute P(x=0)+P(x=1)+P(x=2) in order to find the probability of at most 2 calls at a given minute. P(x=0)=(e -6 *6 0 )/0!=0.00248 P(x=1)=(e -6 *6 1 )/1!=0.0149 P(x=2)=(e -6 *6 2 )/2!=0.0446 Thus P(x=0)+P(x=1)+P(x=2)=0.06198

Yanıt Açıklaması: P(A)=0.40  P(U/A)=0.10  P(U/A).P(A)=0.04 P(B)=0.35  P(U/B)=0.20  P(U/B).P(B)=0.07 P(C)=0.25  P(U/C)=0.05  P(U/C).P(C)=0.0125 P(U)=0,04+0,07+0,0125=0,12

Yanıt Açıklaması: The difference between 60(the highest) and 10(the lowest) is 50 so the correct answer is A