Presentation on theme: "The Keyboard Study Lecture /slide deck produced by Saul Greenberg, University of Calgary, Canada Notice: some material in this deck is used from other."— Presentation transcript:
The Keyboard Study Lecture /slide deck produced by Saul Greenberg, University of Calgary, Canada Notice: some material in this deck is used from other sources without permission. Credit to the original source is given if it is known, image soruce:
The Context Company produces kiosks. walk-up and use situations only mouse input typically for navigating(e.g., menus) but on screen keyboard for occasional text input end-customers vary in typing ability; text entry must be quick to avoid line-ups errors costly (e.g., banking) small displays preferred due to cost, but…
The Idea Qwerty vs Alphabetic, two sizes possible
The problem Which is best? What is the worst case?
Null Hypothesis 1 There is no difference between people's mouse-typing ability as measured in speed (characters per second) and error rate (ratio of extra characters typed over the minimum required) when using a qwerty, alphabetic, or random layouts on a simulated keyboard that is small (measured as …) vs. large (measured as …).
Experimental Design (ANOVA) Type QwertyAlphabeticRandom SizeSmallS 1 ( c hars/sec) S 2 ( c hars/sec) … S n ( c hars/sec) same Largesame Dependent variable: Characters/sec
Experimental Design (ANOVA) Type QwertyAlphabeticRandom SizeSmallS 1 ( errors ) S 2 ( errors ) … S n ( errors) same Largesame Dependent variable: Errors (extra characters)
Null Hypothesis 2 People's typing speeds measured in characters per second when touch-typing vs. mouse-typing is not correlated on the 3 keyboards or their size
Experimental Design (Regression) Mouse typing speed QwertyAlphabeticRandom SmallLargeSmallLargeSmallLarge Physical Typing speed S 1 (t 1,t 2) S 2 (t 1,t 2) … S n (t 1,t 2) same
Issues ? Design random keyboard not really random layout may affect results (guard zones, key size?) Subject selection range of expertise not random generalization Task copy typing vs. free form typing was there sufficient practice, particularly with non-familiar keyboards? (realism) learning curve (sentences same across all conditions) sentence length (does it match real task?) sentence type (punctuation, capitals, etc.) fatigue, boredom motivation to type
Issues ? Ethics violations no approval power situation – had to be a subject Controls varying computers / screens / sound output varying size of displays thus keyboard size environmental conditions: rooms, furniture, computer placement Data collection / analysis extra step in moving data to spreadsheet error prone, tedious errors – is this the best way to record it? unclear when to discard data (e.g., above a certain error rate?) unclear if errors due to keyboard (typing) or mis-reading / skipping words in sentence
BUT Many issues randomized across all conditions Large effects may still emerge Interpretation critical generalization applicability to the problem revisit the scenario In spite of problems, valuable as evidence as interpreted by you
You know now Designing even a simple study requires intense planning and preparation in-depth thinking of all aspects pilots to debug problems understanding limits interpreting results as evidence for / against the problem olimitations, implications, generalization, applicability, etc
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