2021-02-22

asked 2020-12-17

asked 2021-03-09

asked 2021-06-13

asked 2021-06-09

asked 2021-02-08

asked 2021-06-19

When two targets are presented close together in a rapid visual stream, the second target is often missed. Psychologists call this phenomenon the attentional blink (AB). A study published in Advances in Cognitive Psychology (July 2013) investigated whether simultaneous or preceding sounds could reduce AB. Twenty subjects were presented a rapid visual stream of symbols and letters on a computer screen and asked to identify the first and second letters (the targets). After several trials, the subject's AB magnitude was measured as the difference between the percentages of first target and second target letters correctly identified. Each subject performed the task under each of three conditions. In the Simultaneous condition, a sound (tone) was presented simultaneously with the second target; in the Alert condition, a sound was presented prior to the coming of the second target; and in the No-Tone condition, no sound was presented with the second target. Scatterplots of AB magnitude for each possible pair of conditions are shown below as well as the least squares line for each. a. Which pair of conditions produces the least squares line with the steepest estimated slope? b. Which pair of conditions produces the least squares line with the largest SSE? c. Which pair of conditions produces the least squares line with the smallest estímate of σ?

asked 2021-05-22

asked 2021-06-02

The table shows the populations P (in millions) of the United States from 1960 to 2000.
Year 1960 1970 1980 1990 2000 Popupation, P 181 205 228 250 282

(a) Use the 1960 and 1970 data to find an exponential model P1 for the data. Let t=0 represent 1960. (c) Use a graphing utility to plot the data and graph models P1 and P2 in the same viewing window. Compare the actual data with the predictions. Which model better fits the data? (d) Estimate when the population will be 320 million.

(a) Use the 1960 and 1970 data to find an exponential model P1 for the data. Let t=0 represent 1960. (c) Use a graphing utility to plot the data and graph models P1 and P2 in the same viewing window. Compare the actual data with the predictions. Which model better fits the data? (d) Estimate when the population will be 320 million.

asked 2021-05-09

The annual profit for a company that manufactures cell phine accessories can be modeled by the function

\(\displaystyle{P}{\left({x}\right)}=-{0.0001}{x}^{{2}}+{70}{x}+{12500}\) where x is the number of units sold and P is the total profit in dollars.

a. What sales level maximizes the company's annual profit?

b. Find the maximum annual profit for the company.

\(\displaystyle{P}{\left({x}\right)}=-{0.0001}{x}^{{2}}+{70}{x}+{12500}\) where x is the number of units sold and P is the total profit in dollars.

a. What sales level maximizes the company's annual profit?

b. Find the maximum annual profit for the company.

asked 2021-05-14

Which graph used in a residual analysis provides roughly the same information as a scatterplot? What advantages does it have over a scatterplot?