13D

 

Participant

 Number of Colony-forming Units (CFU) before Sanitizer Number of Colony-forming Units (CFU) after Sanitizer
1 11.8 12.1
2 10.8 12.0
3 9.1 3.8
4 14.6 10.1
5 8.2 6.3
6 14.1 11.1
7 13.0 7.2
8 14.0 13.7
 

Participant

 Number of Colony-forming Units (CFU) before Sanitizer Number of Colony-forming Units (CFU) after Sanitizer  

Difference

 
1 11.8 12.1 0.3
2 10.8 12.0 1.2
3 9.1 3.8
4 14.6 10.1
5 8.2 6.3
6 14.1 11.1
7 13.0 7.2
8 14.0 13.7
Participant Reaction Time (in milliseconds)
Cell Phone Use = Yes Cell Phone Use = No
1 636 604
2 623 556
3 615 540
4 672 522
5 601 459
6 600 544
7 542 513
8 554 470
9 543 556
10 520 531
Participant Reaction Time (in Milliseconds) Difference
Cell Phone Use = Yes Cell Phone Use = No
1 636 604
2 623 556 67
3 615 540 75
4 672 522 150
5 601 459 142
6 600 544 56
7 542 513 29
8 554 470 84
9 543 556 -13
10 520 531 11
11 609 599 10
12 559 537 22
13 595 619 24
14 565 536 29
15 573 554 19
16 554 467 87
17 626 525 101
18 501 508 7
19 574 529 45
20 468 470 2
21 578 512 66
22 560 487 73
23 525 515 10
24 647 499 148
25 456 448 8
26 688 558 130
27 679 589 90
28 960 814 146
29 558 519 39
30 482 462 20
31 527 521 6
32 536 543 7
Hypothesis Notation
Null There is no difference between the mean reaction times while using a cell phone and while not using a cell phone.  

 
Alternative  

 
Station Average Temp 1951–2000 Average Temp

1901–1950

 Difference
Sable Island 7.420 6.803 0.617
Manila Int Airport 27.416 26.779 0.637
Perm 2.208 1.670 0.538
Hobart Ellerslie 13.062 12.549 0.513
Bulawayo Goetz 19.183 18.891 0.292
Veraval 26.779 26.404 0.375
Yokohama 15.428 14.534 0.894
Punta Arenas 6.752 6.828 –0.077
Aldergrove 9.012 8.888 0.124
Harare Kutsaga 19.055 18.816 0.239
Bahia Blanca Aero 15.204 14.963 0.241
Cape Leeuwin 16.983 16.608 0.375
Maliye Karmakuly –5.044 –5.036 –0.008
Hobarttasmanwas 12.638 12.439 0.199
Svyatoy Nos Cape 0.263 –0.263 0.527
Apia 26.479 26.380 0.099
Aparri 26.091 25.288 0.803
Syktyvkar 0.894 0.435 0.460
Upernavik –7.286 –7.012 –0.274
Gabo Island 14.924 14.925 –0.001
Antananarivoville 17.741 17.387 0.354
Kumasi 25.854 25.652 0.202
Khartoum 28.874 28.535 0.339
Mahe Seychellesbri 26.872 26.414 0.459
Onslow 24.540 24.154 0.387
Rarotonga Intl 24.157 24.105 0.052
Ponta Delgada 15.676 14.942 0.734
Viljujsk –9.057 –8.854 –0.203
Andenes 3.160 2.600 0.560
Kyzylorda 10.411 9.631 0.780
Port Blair 26.778 26.506 0.271
Chatham Islands 11.132 10.392 0.739
Patient Before After
1 150 146
2 160 159
3 200 200
4 178 174
5 190 189
6 167 160
7 151 148
8 210 198
Mean (
Patient Before After Difference
1 150 146 146–150  4
2 160 159 ­­­159–160 1
3 200 200
4 178 174
5 190 189
6 167 160
7 151 148
8 210 198
Mean (
Null Hypothesis for

Independent Samples

 Null Hypothesis for

Dependent Samples
Alternative Hypothesis

for Independent Samples

 Alternative Hypothesis

for Dependent Samples
Summary Statistics Notation
Population Mean of Difference
Sample Mean of Difference
Population Standard Deviation of Difference
Sample Standard Deviation of Difference
Skill or Concept: I can . . . Questions to check your understanding Rating
from 1 to 5
Identify the differences between independent and dependent samples. 1–7
Calculate the mean of a difference. 8–9

A man using his phone while driving A graph titled “Gabo Island Lighthouse (37.56795, 149.9158E) ID:ASN0008401.” The x-axis is labeled “Years” and the y-axis is labeled “Annual Mean Temperatures (C).” There is a legend in the bottom right corner showing that the line indicates GHCN V4 adj - homogenized. The leftmost point is at approximately (1900, 14.3) and the rightmost point is at approximately (2020, 15.7). The line between these two points is jagged and has a few gaps.

Glossary

dependent sample
a sample where the same variable is recorded for each sample, and there is a logical way to pair the observations from one sample with the observations in the other sample.
independent sample
a sample where samples are independently selected, the same variable is measured for both samples, but there is no logical way to pair an observation from one sample with a particular observation from the other sample.
paired t-test
a test comparing the mean of the differences, 𝜇𝑑,to a hypothesized value, which is often 0, also called a dependent t-test.