Mid-term exam (unit 1-3) Flashcards
What is a Venn diagram?
It’s a box like diagram with all possible outcomes of an experiment
What is an Experiment?
a process that results in one (only) of many observations
What is an Outcome?
observations of the experiment
What is a Sample space?
all the potential outcomes of the experiment
What is a Simple event?
includes only one of the final outcomes
What is a Compound events?
consist of more than one outcome (ex.: at most one man is selected - therefore multiple outcomes)
What is a Population?
consists of all elements being studied in statistics
What is a Sample?
A portion of the population selected for study
What is a Representative Sample?
Sample that represents characteristics of the population
What is a Random sample?
Random selection of the population so each element of the population has a chance of being selected
What is a Sampling with replacement?
elements are put back into the population - therefore contains the same number of items each time a selection is made
What is a Sampling without replacement?
not put back into the population
What is a Census?
A survey that includes every member of the population
What is a Quantitative variable?
a variable that can be measured numerically (ex.: incomes, height, number of houses)
What is a Qualitative variable?
Non-numerical variable (ex.: gender, hair color)
What is a Discrete variable?
Variable whose values are countable (ex.: 0, 1, 2, 3… but not in between intervals like in between 0 to 2)
What is a Continuous variable?
Variable that aren’t countable and has a value over a certain interval (ex.: time, weight…between 30 and 60 minutes)
What is a Frequency distribution for qualitative data?
Frequency distribution for qualitative data lists all categories and the number of elements that belong to each of the categories
How do you calculate midpoint of a class?
(upper limit + lower limit)/2
What is a Frequency distribution for quantitative data?
Frequency distribution for quantitative data lists all the classes and the number of values that belong to each class. It is called grouped data.
What is a Class boundery?
is the midpoint of the upper limit and the lower limit of the next class. (ex.: Class limits 401 to 600 would be 400.5 to less than 600.5)
How do you calculate class width?
(Largest value - Smallest value)/number of class
What is a Right Skewed histogram?
The curve is longer on the right of the histogram
What is a Left Skewed histogram?
The curve is longer on the left of the histogram
What are Outliers?
Values that are very small or very large relative to the majority of the values
What is a Mode?
Value that occurs with the highest frequency in a data set.
What are Quartiles?
are three summary measures that divide a ranked data set into four equal parts.
What are the two properties of probability?
- Probability of an event always lies in the range of 0 to 1 & 2. The sum of all probabilities of all simple events always equals 1.
What means Equally likely outcomes?
Various outcomes who have the same probability of occurence.
What is the relative frequency probability?
the approximation for the probability of an event.
What is a Subjective probability?
probability assigned to an event based on subjective judgment, experience, information and belief.
What is a marginal probability?
is the probability of a single event without consideration for other event. Also called simple probability.
What is a conditional probability?
is the probability of an event to occur given that another event has already occurred. If A and B are two events, the probability of A given B is…. P(A | B)
What are mutually exclusive events?
events that cannot occur together.
What are independent events?
two events are said to be independent if one doesn’t affect the occurrence of the other. For example: A and B are independent events if… Either P(A | B) = P(A) or P(B | A) = P(B)
What are complementary events?
the complement of A, denoted by A (with a bar on top) and read as “A bar” or “A complement” is the event that includes all the outcomes for an experiment that are not in A.
What is the intersection of events?
is given by the outcomes that are common to both events. It is denoted by A and B or AB or A  B (reverse U in between).
What are joint probabilities?
probability of the intersection of two events.
What are the union of events?
is the collection of all outcomes that belong either to A or to B or to both A and B and is denoted by… A or B
What are random variables?
is a variable whose value is determined by the outcome of a random experiment. Usually random variable is denoted by X or Y
What are discrete random variables?
a variable that has countable values (ex.: number of cars, houses or electronics sold)
What are continuous random variable?
a variable that has a value obtained from one or more intervals. (ex.: height of a person, weight of a fish, time to complete an exam)
What is the probability distribution of a discrete random variable?
list all the possible values a random variable can have and their corresponding probabilities.
What is factorial?
the symbol n! read as “n factorial” represents the product of all integers from n to 1 (ex.: 7! = 7 * 6 * 5 * 4 * 3 * 2 * 1 = 5040)
What is a combination?
give the number of ways X elements can be selected from n elements. And is denoted by…nCx.(ex.: 5 cards draw from a 52 cards deck - 52C5)
What are the conditions of a binomial experiment?
A binomial experiment needs to satisfy the following 4 conditions: 1- There are n identical trials. 2- Each trial has only two possible outcomes. 3- The probabilities of the two outcomes remain constant. 4- The trials are independent.
When do we use standard normal distribution?
We use standard normal distribution table when the values of np & nq is greater than 5. So when… np > 5 and nq > 5
What is the continuity correction factor and when is it applied?
is the addition of 0.5 and/or subtraction of 0.5 from the value(s) of x when the normal distribution is used as an approximation to the binomial distribution.
What is the concept of Z values?
The Z values are the horizontal axis on a curve, and determine a position on the curve. The Z value for the mean is always 0.
