Biased & Unbiased
Population - an entire group
Sample - a part of the population
Random Sample - members of the population are chosen at random
Convenience Sample - members of the population that are readily available
BIASED SAMPLE - does not fairly represent the population.
Lets look at
Biased and Unbiased samples
At an assembly 7 out of 10 students who entered the gym were carrying a backpack. Based on this information, if 700 students were at the assembly, how many students could be expected to be carrying a backpack?
To determine the most popular children’s programs, a television station asks parents to call in and complete a phone survey.
To evaluate the defect rate of its memory chips, an integrated circuit manufacturer tests every 100th chip off the production line.
Making inferences with collected data.
Making predictions based on data
The Student Council asked every tenth student in the lunch line how they preferred to be contacted with school news. The results are shown in the table. Suppose there are 684 students at the school. How many can be expected to prefer E-mail? (just type in the number)
A bank randomly surveyed 50 of its customers by mail to find out how customers use its mobile banking service. The survey found that only 11 of the 50 customers used the service.
If the branch has 1,700 customers, about _____ customers use the mobile banking service.
*Only type in the numerical answer.
Zoie completes a report by asking 70 students across campus. She found that 48% of CIAA students do not wash their hands after using the bathroom. What is the sample size?