A brand of popcorn instructs users to microwave for 90–120 seconds on high. A student wonders what the ideal microwave time for popcorn might be and designs an experiment to find out. Bags of popcorn are placed in the microwave for different lengths of time: 90 seconds, 100 seconds, 110 seconds, and 120 seconds. Also, 2 types of microwaves with different power capacity will be used: 900 watts and 1,000 watts. At the end of the experiment, the number of unpopped kernels will be counted.
To increase attendance for a flower show, flower shops in the area offered discount coupons to their customers. Show attendance was higher this year, which the organizers attributed to the many discount coupons attendees used. However, the organizers are warned that weather could be a confounding variable in interpreting the rise in attendance.
To find the ideal temperature for baking muffins, a student plans an experiment to assess the taste and texture of muffins baked at different temperatures. The student pours 3 batches of muffins from the same batter into baking cups and assigns them to different oven temperatures: 350 degrees, 375 degrees, or 400 degrees. Each batch is baked for 10 minutes, and after appropriate cooling time, the muffins are assessed for taste and texture.
A clothing company is considering a new insulation for winter coats. To collect customer satisfaction data on the new insulation, the company is considering two methods.Method 1: The company offers the first 50 employees who volunteer to try out a coat with new insulation if they will report their satisfaction level after one month. At the end of the month, the 50 volunteers describe their satisfaction with the coat's performance.Method 2: The company takes 50 volunteers and randomly assigns 25 of them to coats with the new insulation and the other 25 to coats with the current insulation. All volunteers wear the coats for a month and then describe their satisfaction with the coats’ performance.
An auto-parts store offers a fuel additive that claims to increase a vehicle’s gas mileage. The additive is poured into a vehicle’s gasoline tank after the tank is filled. To measure the claim, 30 taxi drivers receive a bottle of the additive to use the next time they fill their gas tank. The drivers then compare their gas mileage with the additive to their gas mileage before the additive was used.
A farmer would like to determine if a new liquid fertilizer is an improvement compared with the fertilizer currently used. To collect data, two methods are considered.Method 1: Visit a local farm currently using the new liquid fertilizer and measure the heights of plants grown at the farm.Method 2: Choose a plot of land and divide it into 16 smaller plots. Randomly select 8 of the plots to use the new fertilizer and 8 of the plots to use the current fertilizer. Measure and compare plant heights in the 16 plots.
A researcher considers two methods for collecting data to determine if store-brand laundry detergents work as well as name-brand detergents.Method 1: The researcher surveys shoppers as they enter a grocery store. The shoppers are asked which type of detergent they use and then rate the cleanliness of their laundry on a scale from 1 to 10 (with 10 being the cleanest). The ratings of the name-brand detergents are compared to the ratings of the store-brand detergent.Method 2: The researcher creates 10 loads of soiled fabrics and washes 5 of the loads with name-brand detergent and the other 5 with store-brand detergent. Volunteers are asked to assess the cleanliness of the fabrics using a scale from 1 to 10 (with 10 being the cleanest), and the ratings of the name-brand detergents are compared to the ratings of the store-brand detergent.
Many businesses and organizations insist that official communications use professional-looking fonts, such as Times New Roman. Fonts characterized as less professional, such as Comic Sans, should be avoided. A student would like to determine if font choice makes a difference in the average grade on a typed response in English classes. There are currently four English classes available from which the student can collect data, and each class has a similar writing assignment. At the start of the assignment, students are randomly assigned a font, either Times New Roman or Comic Sans, and then complete the assignment. The teachers grade the assignments, and the mean grade for each font is found.
Two methods are proposed to measure the effectiveness of a brand of sunscreen.Method A: Survey adults visiting a beach on a busy weekend. Ask each adult which brand of sunscreen they are using, and assess their arms for sun exposure.Method B: Volunteers are randomly assigned to one of two brands of sunscreen. Each volunteer is asked to report back at the end of the day, and their arms are assessed for sun exposure.
An article in a psychology journal claims that young students who play a musical instrument tend to have higher test scores on state math exams.
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