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Stats
Midterm
| Question | Answer |
|---|---|
| The entire collection of individuals about which information is being sought is called a _____ | population |
| A ____ sample is one in which the population is divided into groups and a random sample of groups is drawn. | cluster |
| A ___ sample is one in which the population is divided into groups and a random sample is drawn from each group | stratified |
| T or F: A voluntary response is always a reliable way to sample | False |
| Variables that classify individuals into categories are called ___ | qualitative |
| A ___ variable is a quantitative variable whose possible values cannot be listed | continuous |
| In a data set, the number of items that are in a particular category is called the ___ | frequency |
| T or F: IN a frequency distribution, the sum of all frequencies is less than the total number of observations | FALSe |
| IN a data set, the proportion of items that are in a particular category is called the ___ frequency | relative |
| when the right half of a histogram is a mirror image of the left side, the histogram is ____ | symmetric |
| a histogram is skewed to the left if its ___ tail is longer than its ___tail | left tail longer than its right tail |
| The ___ frequency of a class is the sum of the frequencies of that class and all previous classes | cumulative |
| a # that is not affected much by extreme values, such as the median, is ___ | resistant |
| Is the mean resistant? | NO! |
| The ___ is the number that splits the data set in half | median |
| The ___ is calculated by summing all data values and dividing by how many there are | mean |
| When the histogram is skewed to the LEFT, the mean is ___ than the median | less |
| When the histogram is skewed to the RIGHT, the mean is __ than the median | greater |
| T or F: the mode is always a number that appears in the data set | true |
| How do you compute sample variance? | enter the data into the calculator and run the 1-Var Stats command. Recall that Sx is the sample standard deviation and the sample variance is the square of this. Be sure to include several decimal places when you square the value to ensure accuracy. |
| How do you compute sample standard deviation? | enter the data into the calculator and run the 1-Var Stats command. Recall that Sx is the sample standard deviation. |
| How do you compute population standard deviation? | enter the data into the calculator and run the 1-Var Stats command. Recall that the population standard deviation is denoted by sigma. |
| ___ equals the 25th percentile | Q1 |
| ___ equals the median | Q2 (50th percentile) |
| ___ equals the 75th percentile | Q3 |
| ___ is the difference between Q3 and Q1 (Q3 - Q1) | IQR |
| ___ tells how many standard deviations that a value is away from the mean | z-score |
| ___ is a value that is considerably larger or considerably smaller than most values in a data set | outlier |
| What is the formula to compute z score? | (x-mean) / (standard deviation) |
| What is the formula to determine a data value when you already have the z-score? | mean + standard deviation (z-score) |
| How do you find the pth percentile? | 1. Arrange in increasing order 2. Formula L = (p/100)(n) 3. If L is a whole number, find the avg of L and L + 1 If L is NOT a whole number, round up to the nearest whole # |
| Finding : "What percentile is... "? | 1. arrange in increasing order 3. Compute formula: 100*(number of values less than x + 0.5) / (number of values in data set) |
| ___ : The collection of all possible outcomes of a probability experiement | sample space |
| ___ : an outcome or collection of outcomes from a sample space | event |
| ___: as a probability experiment is repeated, the proportion of times that a given outcome occurs will approach its probability | law of large numbers |
| ___ : denotes the probability of event A and must always be between 0 and 1 | P(A) |
| ___ : an event whose probability is small. The cutoff is usually 0.05 | unusual event |
| ___ = P(A) + P(B) - P(A and B) | P (A or B) |
| ___ : Means that P (A and B) = 0 | mutually exclusive |
| ___ : the event that A does not occur | complement of A |
| ___ : P(Ac) = 1 - P(A) | the rule of complements |
| If P(A) = 0.28 and P(B) = 0.45 . If A and B are mutually exclusive, find P(A or B). For this problem. you don't do the normal P(A) + P(B) - P (A and B) because they are mutually exclusive. You just add P (A) and P (B) together. | .28 + .45 = .73 |
| ___ : A probability that is computed with the knowledge of additional information. | conditional probability |
| __ : P(A)P(B|A) or P(B)P(A|B) | P (A and B) |
| __ : The occurrence of one event does not affect the probability that the other event occurs. | independent |
| If events A and B are independent, then P (A and B) = | P(A)P(B) |
| How do you compute SD when given probability and number of participant n the study | square root of np(1-p). |
Created by:
jjohns53grad2