[STATISTICS]-"Population and Sample"

the percentage of surveyed homeowners who own at least one dog--? population Statistic

population 1. all [y/n] Sample 1. portion of Popu 2. serve [y/n] its Statistic

Types of Sampling Methods --Simple Random—Every participant has equal chance of being chosen --A simple random sample should be used if the population is not well understood or there are no groups within the population that need to be analyzed individually

--Systematic—choosing every 5th or 8th or 'kth' person—having a 'system' --Convenience—Readily available or easily accessible --Stratified—Divide into groups, then sample proportionate number from each group

Variables and Measures of Data Levels of Measurement --Nominal—Name or Category—used for identification only --Ordinal—think of order or ranking, #1 or #2 favorite movie—Numbers, but doing math doesn't make sense --Interval—Think of a temperature scale where 10 degrees is not twice as warm as warm as 5 degrees—just a different place on the scale

--also, 0 degrees doesn't mean there is an absence of warmth --Time fits in this category --No 'inherent' zero --Ratio—Think of money or age where you could have multiples of each other --0 dollars does mean there is none --money or prices or length or length of time

how to find Skewers and

-find medium ? -find mean?

the percentage of all homeowners who own at least one dog-- 1. Statistics? 2.population? 3. Parameter?

Check parameter 1. numberic vale of Popo 1. Num [y/n] yes [per] 2. all home owner [Population]

specific responses to the survey— 1. Data? 2. Variable? 3. Population?

Data and Variable

Qualitative (Qualities or Labels) vs Quantitative (Quantities—could be Discrete or Continuous) --Discrete (countable—Number of People or things or shoe sizes) --Continuous (measurable—time, distance, weight, etc)

Explanatory (Influences the other) vs Response (Responds to the other) Variable --Independent Variable --Dependent Variable --grade level --time spent studying --gender --political party --Number of siblings --GPA --height --red blood cell count ---what for order

the 125 homeowners surveyed, 1. population 2. Data 3. Variable

check sample

what is Skewed Data?

data that has a main concentration of large values with several other much smaller values, or vice versa - if there is a large concentration of small values with several other much larger values

Question Is the statement below true or false? A sample is all individuals, objects, or measurements whose properties are being studied. Select the correct answer below: True False

false A population is defined as all individuals, objects, or measurements whose properties are being studied. A sample is defined as a subset of the population studied.

Question Nick wants to estimate the percentage of homeowners that own at least one dog. He surveys 150 randomly selected individuals to determine whether or not they own dogs. What is the sample? Select the correct answer below: the percentage of surveyed 5Homeowners that own at least one dog 1.all homeowners 2.the percentage of all homeowners that own at least one dog 3.specific responses to the survey 4. the 150 homeowners surveyed

he 150 homeowners surveyed A sample is a specific subset of the entire group of individuals being studied. In this case, the sample is the 150 homeowners surveyed.

Question Anna wants to estimate the mean number of siblings for each student in her school. She records the number of siblings for each of 75 randomly selected students in the school. What is the statistic? 1 the specific number of siblings for each randomly selected student 2 all the students in the school 3 the mean number of siblings for all students in the school 4 the mean number of siblings for the randomly selected students 5the 75 randomly selected students

the mean number of siblings for the randomly selected students A statistic is a numerical characteristic of the sample. In this case, the statistic is the mean number of siblings for the randomly selected students.

Population(ALL) vs Sample(Surveyed or Part of the Pop) and Parameter(Pop.) vs Statistic(Sample)

what is Population ? what is the Sample?

Skewness and Standard Deviation --Standard Deviation—'How spread out is the data' --more spread out—larger std dev --less spread out—smaller std dev --Skewed Left or Right--Given a median and mean --if is to the left on the number line, then it is skewed Left --if is to the right on the number line, then it is skewed Right --Skewed Left or Right—'Which way does the tail go???'

z = number of standard deviations to the left (negative) or right (positive) of the mean m = mean = 6 o = std dev = 3 x = data value = 15 z = (x - m)/o = (15-6)/3 = 9/3 = 3 SAT z = (1650-1500)/300 = .5 ACT z = (23-20.8)/4.4= .5 --Most Inconsistent Wait times—Largest Standard Deviation