In: Statistics and Probability
It is believed that 11% of all Americans are left-handed. A college needs to know how many left-handed desks to place in the big lecture halls being constructed on its campus. In a random sample of 180 students from that college, whether or not a student was left-handed was recorded for each student. The college wants to know if the data provide enough evidence to show that students at this college have a different percentage of left-handers than the general American population? State the random variable, population parameter, and hypotheses. State the Type I and Type II errors in the context of this problem.
a) The symbol for the random variable involved in this problem is ______
The wording for the random variable in context is as follows: _________
b) The symbol for the parameter involved in this problem is __________
The wording for the parameter in context is as follows: ________
c) Fill in the correct null and alternative hypotheses:
H0:_______
HA:_______
d) A Type I error in the context of this problem would be:
e) A Type II error in the context of this problem would be:
Answer: It is believed that 11% of all Americans are left-handed. A college needs to know how many left-handed desks to place in the big lecture halls being constructed on its campus. In a random sample of 180 students from that college, whether or not a student was left-handed was recorded for each student. The college wants to know if the data provide enough evidence to show that students at this college have a different percentage of left-handers than the general American population?
Solution:
a) The symbol for the random variable involved in this problem is :
The symbol for the random variable is .
The wording for the random variable in context is as follows:
In random sample of 180 the percentage of all students from that college that are left-handed.
b) The symbol for the parameter involved in this problem is:
the symbol for the parameter is p
The wording for the parameter in context is as follows:
11% of all students from that college are left-handed.
c) Fill in the correct null and alternative hypotheses:
Null hypothesis, Ho: p = 0.11
Alternative hypothesis, Ha: p > 0.11
d) A Type I error in the context of this problem would be:
Type I error is rejecting Ho, when Ho is true
Rejecting that the percentage of all students from the college that are left-handed is 11% when the percentage is really 11%.
e) A Type II error in the context of this problem would be:
Type II error is fail to reject Ho, when Ho is false
Failing to reject that the percentage of all students from the college that are left-handed is 11% when the percentage is really higher than that.