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PHY 117M, spring 201458055Ariel Chen (ac47386)Lab partners: Diana OntiverosMariano Aufiero

Chapter 1: Reaction Time

1. Table 1: Sample Calculations of the mean and standard deviation sConditionMean (ms)Standard Deviation (ms)

Audio Reaction Time152.9551.81

Visual Reaction Time146.7138.50

Random Visual Reaction Time357.5560.81

Mean = =

Standard Deviation = =

2.Table 2: Frequency table for 100 measurements of audio reaction time; measurements on the border are grouped into the higher interval (e.g. 100 is grouped in the 100-150 interval)IntervalTallyFrequency

10-50IIII4

50-90I1

90-130IIIIIIIIIIIIIIIIIIIIIII23

130-170IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII49

170-210IIIIIIIIIIIII13

210-250IIIII5

250-290III3

290-330I1

330-370

370-410I1

3.Graph 1: Histogram of Audio Response Times

-2s-s+s+2sProbability density (1/10000)12511210087.575.062.550.037.525.012.50Probability0.500.450.400.350.300.250.200.150.100.050

4. Percentage of measurements between s and + s: ~80%Percentage of measurements between 2s and + 2s: ~90%

In order to determine the mean and standard deviations of a histogram that I have never seen before, I would look if the mode of the distribution was approximately normal, then determine the standard deviation by finding the range of the distribution that contained about 80% of the measurements and dividing it by two.

5. Random sample of 20 audio response time measurements157139128150136

120133127100298

199148201140136

154133131137414

Mean (ms)Standard Deviation (ms)

164.0572.13

Mean = =

Standard Deviation = = Alice Chen (ac48272)PHY 117M (59065)2/10/14

6.Table 4: Z-values for boundaries 2 and 1 standard deviations away from the meanBoundary-2s-s+s+2s

Value49.3101.1204.8256.6

Z-value-2-112

Z = = = -2

7.Tallest bar in histogram: 130-170Probability that a randomly chosen measurement of audio response time will fall between 130 and 170 ms:Z(130) = = -0.444P(x