Does the description correspond to an observational

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Does the description correspond to an observational study or an experiment?A student earned grades of 84, 78, 84, and 72 on her four regular tests. She earned a grade of 78 on the final exam and 86 on her class projects. Her combined homework grade was 87. The four regular tests count for 40% of the course grade, the final exam counts for 30%, the project counts for 10%, and homework counts for 20%. What is her weighted mean grade? Round to one decimal place.A.81.2B.80.2C.82.1D.81.3
A department store has daily mean sales of $28,372.72. The standard deviation of sales is $2000. On Tuesday, the store sold $34,885.21 worth of goods. Find Tuesday's z-score. Was Tuesday a significantly good day?
Determine whether the given procedure results in a binomial distribution. If not, state the reason why.Rolling a single die 53 times, keeping track of the "fives" rolled.
The Precision Scientific Instrument Company manufactures thermometers that are supposed to give readings of 0degrees°C at the freezing point of water. Tests on a large sample of these thermometers reveal that at the freezing point of water, some give readings below 0degrees°C (denoted by negative numbers) and some give readings above 0degrees°C (denoted by positive numbers). Assume that the mean reading is 0degrees°C and the standard deviation of the readings is 1.00degrees°C. Also assume that the frequency distribution of errors closely resembles the normal distribution. A thermometer is randomly selected and tested. A quality control analyst wants to examine thermometers that give readings in the bottom 4%. Find the temperature reading that separates the bottom 4% from the others. Round to two decimal places.
Scores on the SAT test have a mean of 1518 and a standard deviation of 325. Scores on the ACT test have a mean of 21.1 and a standard deviation of 4.8. Which of the following choices is not true?A.An SAT score of 1490 has a z-score of minus−0.09.B.The ACT score of 17.0 is relatively better than the SAT score of 1490.C.An ACT score of 17.0 has a z-score of minus−0.85.D.The SAT score of 1490 is relatively better than the ACT score of 17.0.
The weights of college football players are normally distributed with a mean of 200 pounds and a standard deviation of 50 pounds. If a college football player is randomlyselected, find the probability that he weighs between 170 and 220 pounds. Round to four decimal places.

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