Math Problem Statement

Doctorates The following table shows the annual number of PhD graduates in a country in various fields. Natural Sciences Engineering Social Sciences Education 2010 5,000 7,600 7,800 5,200 2012 5,400 8,400 8,400 4,800 2014 5,900 9,600 8,700 4,800 2016 6,200 9,500 9,000 5,100 2018 6,300 10,200 8,900 4,800 2020 6,700 10,800 8,900 4,600 (a) With x = the number of social science doctorates and y = the number of education doctorates, use technology to obtain the regression equation. (Round coefficients to three significant digits.)

Solution

To find the regression equation for both the number of social science doctorates (xx) and the number of education doctorates (yy) over time, we need to set up a regression analysis for each data set based on the year.

Given the dataTo find the regression equation for both the number of social science doctorates (xx) and the number of education doctorates (yy) over time, we need to set up a regression analysis for each data set based on the year.

Given the

Social Sciences (xx):

  • 2010: 7,800
  • 2012: 8,400
  • 2014: 8,700
  • 2016: 9,000
  • 2018: 8,900
  • 2020: 8,900

Education (yy):

  • 2010: 5,200
  • 2012: 4,800
  • 2014: 4,800
  • 2016: 5,100
  • 2018: 4,800
  • 2020: 4,600

For the regression analysis, we'll assign numerical values to the years where:

  • t=0t = 0 for 2010
  • t=2t = 2 for 2012
  • t=4t = 4 for 2014
  • t=6t = 6 for 2016
  • t=8t = 8 for 2018
  • t=10t = 10 for 2020

This allows us to perform a linear regression for both xx (social sciences) and yy (education) doctorates.

Let me calculate the regression equations.The regression equations for the number of doctorates are as follows:

For Social Sciences (xx):

x(t)=8095.24+104.29tx(t) = 8095.24 + 104.29t This equation suggests that the number of social science doctorates increases by approximately 104.29 per 2-year period.

For Education (yy):

y(t)=5076.1938.57ty(t) = 5076.19 - 38.57t This equation indicates that the number of education doctorates decreases by approximately 38.57 per 2-year period.

Where tt is the number of years since 2010 (i.e., t=0t = 0 for 2010, t=2t = 2 for 2012, etc.).

Let me know if you'd like further details or if you have any questions!

Here are some related questions:

  1. How accurate are these models in predicting future doctorate numbers?
  2. What might explain the decreasing trend in education doctorates?
  3. How would a quadratic model compare to the linear one?
  4. Could external factors be influencing these trends?
  5. How does the trend in social sciences compare to engineering?

Tip: When interpreting regression equations, remember that the slope indicates the rate of change over time!

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Math Problem Analysis

Mathematical Concepts

Linear Regression
Data Analysis
Algebra

Formulas

Linear regression equation: y = mx + b
Slope formula: m = (Σ(xy) - n*mean(x)*mean(y)) / (Σ(x^2) - n*(mean(x)^2))

Theorems

Least Squares Method

Suitable Grade Level

College Level