Answer:
Placebo effects or experimenter bias are likely to affect results
Explanation:
Due to the fact that everyone in the class is quite excited about being taught by the new method, the most obvious error will be the placebo effect, a phenomenon where some people would perceive some benefit of some sort because they already know what is expected of them. Experimental bias may also occur since everyone is quite excited, but then he chooses to allocate the teaching method to a random half and the old method to the other half. This can cause the students allocated to the old method to provide bad reports and those who are allocated to the new method to claim excitement.
Http://m.historyextra.com/feature/complex-crimea-history-relationship-Russia-Ukraine-Crimea
Answer: <em>The upper caste was composed of rulers, nobles and priests. The middle caste were businessmen, merchants and soldiers. The lower caste was made up of farmers and slaves. Rulers: Each city had a ruling family.</em>
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<em>Answer:</em>
<em>astigmatism </em><em> </em>
<em>Explanation:</em>
<em><u>Astigmatism</u></em><em> is described as one of the common conditions associated with an eye that leads to developing blurred vision in a person. Astigmatism generally occurs when an individual's cornea i.e, the eye's front cover is being irregularly shaped or at times due to the lens curvature present inside his or her eye. Astigmatism can cause distorted, blurry, or fuzzy vision. </em>
<em><u>As per the question, Nigel is exhibiting symptoms of astigmatism.</u></em>