Qualitative and quantitative sampling. Who are they Black/Blue/Green/Red Thin/Bold...
-
Upload
stephen-mclaughlin -
Category
Documents
-
view
215 -
download
1
Transcript of Qualitative and quantitative sampling. Who are they Black/Blue/Green/Red Thin/Bold...
![Page 1: Qualitative and quantitative sampling. Who are they Black/Blue/Green/Red Thin/Bold Smiling/Normal/Sad](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649f0b5503460f94c1ec94/html5/thumbnails/1.jpg)
Qualitative and quantitative sampling
![Page 2: Qualitative and quantitative sampling. Who are they Black/Blue/Green/Red Thin/Bold Smiling/Normal/Sad](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649f0b5503460f94c1ec94/html5/thumbnails/2.jpg)
Who are theyBlack/Blue/Green/RedThin/BoldSmiling/Normal/Sad
![Page 3: Qualitative and quantitative sampling. Who are they Black/Blue/Green/Red Thin/Bold Smiling/Normal/Sad](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649f0b5503460f94c1ec94/html5/thumbnails/3.jpg)
Non-Probability Sampling
• Haphazard sampling
• Quota sampling
• Purposive sampling
• Snowball sampling
• Deviant case sampling
• Sequential sampling
• Theoretical sampling
![Page 4: Qualitative and quantitative sampling. Who are they Black/Blue/Green/Red Thin/Bold Smiling/Normal/Sad](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649f0b5503460f94c1ec94/html5/thumbnails/4.jpg)
Haphazard / Accidental / Convenience sample
![Page 5: Qualitative and quantitative sampling. Who are they Black/Blue/Green/Red Thin/Bold Smiling/Normal/Sad](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649f0b5503460f94c1ec94/html5/thumbnails/5.jpg)
Quota sample
![Page 6: Qualitative and quantitative sampling. Who are they Black/Blue/Green/Red Thin/Bold Smiling/Normal/Sad](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649f0b5503460f94c1ec94/html5/thumbnails/6.jpg)
Purposive sample
![Page 7: Qualitative and quantitative sampling. Who are they Black/Blue/Green/Red Thin/Bold Smiling/Normal/Sad](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649f0b5503460f94c1ec94/html5/thumbnails/7.jpg)
Snowball sample
![Page 8: Qualitative and quantitative sampling. Who are they Black/Blue/Green/Red Thin/Bold Smiling/Normal/Sad](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649f0b5503460f94c1ec94/html5/thumbnails/8.jpg)
Deviant case sampling
![Page 9: Qualitative and quantitative sampling. Who are they Black/Blue/Green/Red Thin/Bold Smiling/Normal/Sad](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649f0b5503460f94c1ec94/html5/thumbnails/9.jpg)
Sequential sampling(= purposive + collect cases until marginal utility drops significantly)
![Page 10: Qualitative and quantitative sampling. Who are they Black/Blue/Green/Red Thin/Bold Smiling/Normal/Sad](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649f0b5503460f94c1ec94/html5/thumbnails/10.jpg)
Theoretical sampling
• Based on (grounded) theory– Theory develops from initial research– Cases are selected that are expected to
further deepen the theory• Eg. Theory developed from data collected during
day time next collect data at night
![Page 11: Qualitative and quantitative sampling. Who are they Black/Blue/Green/Red Thin/Bold Smiling/Normal/Sad](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649f0b5503460f94c1ec94/html5/thumbnails/11.jpg)
Probability SamplingPopulation
(delinquents)N
Target population(thieves)
Sampling frame(known as
“thieves” by police)
Samplen
Sampling ratio
Nn
![Page 12: Qualitative and quantitative sampling. Who are they Black/Blue/Green/Red Thin/Bold Smiling/Normal/Sad](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649f0b5503460f94c1ec94/html5/thumbnails/12.jpg)
Probability Sampling
• Population is often (usually) unknown,therefor a population is described with theoretical values (parameters) eg: N(,)
• Random sample– Equal chance for all elements to figure in the sample
• Sampling error (deviation from representativeness)• Sampling distribution• Central limit theorem
Other demos : 1, 2
![Page 13: Qualitative and quantitative sampling. Who are they Black/Blue/Green/Red Thin/Bold Smiling/Normal/Sad](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649f0b5503460f94c1ec94/html5/thumbnails/13.jpg)
Theoretical sampling distribution
Population
Sample Sample Means Samples of 2
Cases
Samples of 4
Cases
Samples of 6
Cases .5 1 1.0 1 15 -1.75 2 2 2.0 - 2.67 5 10 2 2.75 - 3.25 3 25 10 3.33 - 4.00 8 43 52 4.17 - 4.83 5 50 82 5.00 - 5.67 8 43 52 5.75 - 6.25 3 25 10 6.33 - 7.0 5 10 2 7.25 - 7.5 2 2 8.0 1 8.5 1 No. of samples 45 210 210 Mean of s. means 4.5 4.5 4.5 % sample means > 4.00 and < 5.00
11 24 39
CASE A B C D E F G H I J Mean
SCORE 0 1 2 3 4 5 6 7 8 9 4.5
![Page 14: Qualitative and quantitative sampling. Who are they Black/Blue/Green/Red Thin/Bold Smiling/Normal/Sad](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649f0b5503460f94c1ec94/html5/thumbnails/14.jpg)
Probability sampling techniques
• Simple Random Sample (SRS)– Random numbers
• Systematic sampling (danger: cycles or patterns in sampling frame)– Random start– Sampling interval
• Stratified sampling– Subpopulating (stratification)– SRS from all strata
• Cluster sampling– Identify clusters and draw SRS from those– Then draw SRS of elements from the selected clusters– Within-Household sample: whom should researcher ask? (always first
to pick up the phone or open the door...?)– Probability Proportionate to Size (equal probabilities)
• Random Digit Dialling
A link
![Page 15: Qualitative and quantitative sampling. Who are they Black/Blue/Green/Red Thin/Bold Smiling/Normal/Sad](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649f0b5503460f94c1ec94/html5/thumbnails/15.jpg)
Simple random sample1 2 3 4 5 6 7 8 9 10
11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30
31 32 33 34 35 36 37 38 39 40
41 42 43 44 45 46 47 48 49 50
51 52 53 54 55 56 57 58 59 60
61 62 63 64 65 66 67 68 69 70
71 72 73 74 75 76 77 78 79 80
81 82 83 84 85 86 87 88 89 90
91 92 93 94 95 96 97 98 99 100
101 102 103 104 105 106 107 108 109 110
111 112 113 114 115 116 117 118 119 120
121 122 123 124 125 126 127 128 129 130
131 132 133 134 135 136 137 138 139 140
141 142 143 144 145 146 147 148 149 150
151 152 153 154 155 156 157 158 159 160
161 162 163 164 165 166 167 168 169 170
171 172 173 174 175 176 177 178 179 180
181 182 183 184 185 186 187 188 189 190
191 192 193 194 195 196 197 198 199 200
![Page 16: Qualitative and quantitative sampling. Who are they Black/Blue/Green/Red Thin/Bold Smiling/Normal/Sad](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649f0b5503460f94c1ec94/html5/thumbnails/16.jpg)
Systematic sample1 2 3 4 5 6 7 8 9 10
11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30
31 32 33 34 35 36 37 38 39 40
41 42 43 44 45 46 47 48 49 50
51 52 53 54 55 56 57 58 59 60
61 62 63 64 65 66 67 68 69 70
71 72 73 74 75 76 77 78 79 80
81 82 83 84 85 86 87 88 89 90
91 92 93 94 95 96 97 98 99 100
101 102 103 104 105 106 107 108 109 110
111 112 113 114 115 116 117 118 119 120
121 122 123 124 125 126 127 128 129 130
131 132 133 134 135 136 137 138 139 140
141 142 143 144 145 146 147 148 149 150
151 152 153 154 155 156 157 158 159 160
161 162 163 164 165 166 167 168 169 170
171 172 173 174 175 176 177 178 179 180
181 182 183 184 185 186 187 188 189 190
191 192 193 194 195 196 197 198 199 200
![Page 17: Qualitative and quantitative sampling. Who are they Black/Blue/Green/Red Thin/Bold Smiling/Normal/Sad](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649f0b5503460f94c1ec94/html5/thumbnails/17.jpg)
Stratified sampling
![Page 18: Qualitative and quantitative sampling. Who are they Black/Blue/Green/Red Thin/Bold Smiling/Normal/Sad](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649f0b5503460f94c1ec94/html5/thumbnails/18.jpg)
Cluster sampling
![Page 19: Qualitative and quantitative sampling. Who are they Black/Blue/Green/Red Thin/Bold Smiling/Normal/Sad](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649f0b5503460f94c1ec94/html5/thumbnails/19.jpg)
How large should a sample be?
• ... It depends on...– population size ,
characteristics (homogeneousless / heterogeneousmore)
– spread of the data (sd)– Purposes (descriptive?
testing? (power))
Population SampleSampling
ratio
200 171 85.5%
500 352 70.4%
1000 543 54.3%
2000 745 37.2%
5000 960 19.2%
10000 1061 10.6%
20000 1121 5.6%
50000 1160 2.3%
100000 1173 1.2%
![Page 20: Qualitative and quantitative sampling. Who are they Black/Blue/Green/Red Thin/Bold Smiling/Normal/Sad](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649f0b5503460f94c1ec94/html5/thumbnails/20.jpg)
Haphazard sampling= Accidental-, Convenience-,
Availability -
Cluster sampling
Multi stage sampling
Quota sampling
Random sampling
Snowball sampling
Stratified sampling
Systematic sampling