Name
STA 2023 PRACTICE FINAL SPRING 2004
The Final Exam counts 200 points!!
#1 – 32 are worth 4 points each.
1) A school with 250 students surveys 100 of them about their study hours per week and finds the mean is 15.3 hours. Is this a parameter or a statistic?
2) A math teacher gives half of her classes a practice test on every chapter and half do not. She then compares the average grade for each class. Is this study observational or experimental?
3) Is the number of tables (z, t, etc.) you need for this class a continuous or discrete variable?
4) You obtain the scores on Test 2 for everyone in this class. Give the BEST level of measurement: ratio, interval, ordinal, or nominal?
5) Voters are classified as Democrat, Republican or Other. Give the BEST level of measurement: ratio, interval, ordinal, or nominal?
6) Find the probability that 
& round to 4
decimal places.
7) Find the probability that z is between -1.8 and 2.15 & round to 4 places.
8) If m = 100 and s = 15, find the probability that x is between 78 and 113 & round to 4 places.
9)
If the mean test score is 74.6 and standard deviation is 5.7, find the
probability that your score is passing (more than 69.5) & round to 4
places.
10)
If the mean test score is 72.1 and standard deviation is 10.2, find the score
which is the 20th percentile & round to the appropriate whole
number.
11) A survey of 300 college students found 198 of them owned a PC. What is this proportion?
12) Find the standard deviation for the proportion in # 11 to the nearest thousandth.
13) Find the required sample size
for a survey for a confidence level of 96% with a margin of error of .04 and a
pilot study had 
.
14) Find the required sample size
for a survey for a confidence level of 98% with a margin of error of .03 and an
old study had 
= .25
For #15 – 17, give the
standardized score for each. Your answer MUST specify “
or “
”. Round z’s to 2 places and t’s to 3 places.
15) A random sample of 250 people
has 
and 
where the population
mean is 100.
16) A random sample of 16 people
has and and m =
100.
17) A random sample of 150 people
has 
& a study from 5
years ago had 
18) A random sample of 25 people
had 
&
. Find the 99% confidence interval for the population mean
(to the nearest hundredth). Write as algebraic “between” expression.
19) A random sample of 200 people
has 
140. Find the 96% confidence interval for the population
proportion. ( to the nearest hundredth)
20) A random sample of 350 people
had 
8.1 and 
2.3. Find the 98% confidence interval for the population mean
(to the nearest hundredth)
21) A confidence interval is an example of which type of statistics? ( “descriptive” or “inferential”)
22) A list of all students is made by their major and 20 are randomly chosen from each major . What type of sample is this? (Random, stratified, cluster, systematic, or convenience)
Use this sample of test scores to answer #23 – 32; Round answers to the nearest tenth where necessary.
85 53 64 98 85 76 72 85 91 82 73 94 95 84 92 69
75 74 81 85 64 94 77 57 45 76 66 72 92 71 82 70
23) Find the mean.
24) Find the median.
25) Find the mode(s).
26) Find the range.
27)
Find 
.
28)
Find 
.
29)
Find the standard deviation.
30)
Find the variance.
31) Find the standardized score (
score) for a data value of 50 (to the nearest hundredth)
32)
Is the data value 50 “unusual” or “not unusual”?
Answer list:
1) Statistic
2) Experimental
3) Discrete
4) Ratio
5) Nominal
6) .8944
7) .9483
8) .7357
9) .8145
10) 64
11) .66
12) .027
13) 5910
14) 1132
15) 
16) 
17) 
18) 
m
19) 
20) 
m
21) inferential
22) stratified
23) 77.5
24) 76.5
25) 85
26) 53
27) 70.5
28) 85
29) 12.8
30) 162.6
31) 
32) unusual