A scientist collected data in 10 trials comparing tired students’ and awake students’ test scores. Trial Tired Average Score Awake Average Score 1 34% 67% 2 56% 88% 3 60% 90% 4 58% 86% Which trial was the least precise and is unlikely to be reproducible? Trial 1 Trial 2 Trial 3 Trial 4

Trial 1

Explanation:

Precision can be simply put as how close the second value is to the first one

Given

score 1 : 34% ,67%

average = 34+67 /2 =50.5

Deviations = 50.5-34 =16.5 and 50.5-67 = -16.5

Average of deviations = (16.5 + -16.5 )/2 = 0.00

score 2 : 56% ,88%

Average = 56+88 /2 =72

Deviations= 72-56 = 16 , 72-88 = - 16

Average of deviation = 0.00

score 3 : 60% ,90%

Average = 60+90 /2 = 75

Deviations : 75-60 =15 , 75-90 = -15

Average of deviations = 0.00

Score 4 : 58% , 86 %

Average : 58+86 /2 = 72

Deviations = 72- 58 = 14 , 72-86 = -14

Average of deviation = 0

Scores in trial 1 are the least precise and unlikely to be reproducible because the deviation of score is high.

trial 4

Explanation:

- calcium has greater affinity to bond with electron receptors than hydrogen does and hence, it has the ability to replace hydrogen in most of its compounds.

- lithium has 2 valence electrons in the product because it can make only 1 bond with hydrogen. beryllium has 4 valence electrons in the product because it can only make 2 bonds. it has fewer electrons than neon and can react with electron donors. each hydrogen has 2 valence electrons, the same as helium.

- the covalent bond formed between carbon and hydrogen is polar because carbon is more electronegative than hydrogen and it attracts the bonded electron pair closer to itself, thus giving hydrogen a partial positive charge.

- a hydrogen bond is a relatively weak bond that hydrogen atoms make with the electronegative atoms nitrogen, oxygen or fluorine.

so the best choice is a.) 2 calcium (ca) atoms

mark him as !