Basic Applied Statistics 200
Solutions to Midterm 1
-
- (vi) sigma (we have information
about the popuation, not a sample)
- 0, 10, 20, 30, 40, 50, 60
- 10 (mean minus 2 sds)
- 16% (because 68% are between 20 and 40)
- mean - 2.5 sds=30-2.5(10)=5
- (iii) (because it's not even 1 sd above the mean)
-
- (iii) Researchers could have observed who received flowers naturally, or they could have sent the flowers themselves.
- (ii) It would be too expensive to send flowers to a large group of subjects. An observational study would be inexpensive, and could include a large
number of individuals.
- (i) (flowers or no flowers)
- (i) Patients who receive flowers from family and friends may receive
other beneficial support measures from those people, such as closer supervision
of their medical care.
-
- (iii) The treatment (receiving food or not) was imposed.
- (iv) (The experimenters may have sent the dogs other cues besides
rewarding their partner or not. Being "upset" is not easy to define. The setting was very artificial.)
- (ii) Part (b) illustrates flaws in the study design. "Using several
dozen dogs of a variety of backgrounds and breeds" suggests the sampling design is not problematic.
-
- (i)
- (iii)
- (iii)
- (iv) (Q->Q)
-
- (iii)
- 2 (compare proportions in (a))
- 116/874=0.13
- (116/874)(437)=58 or 0.13(437)=57
- 79 (number in the upper left square)
- 79+37+358=474
-
- (iii) -0.57 (negative and moderate), negative square root of 0.325
- (ii) (because the direction is negative)
- (iii)
- (ii) (discussed in Lecture 12)
- 13.8-0.24(31)=6.36
- 10.60-6.36=4.24
- (iii)(since s=4.36)
Extra Credit: r=0 if s and s_y are close (See Lecture 12).
[ Home
| Calendar
| Assignments
| Handouts
]
|