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Stock-Based Compensation (Tables)
3 Months Ended
Apr. 01, 2018
Schedule of Estimated Fair Value of TSR Performance-Based Restricted Stock Unit Awards Assumptions

The fair value was estimated using the Monte Carlo simulation model with the following assumptions:

 

     For the Three Months
Ended
 
     April 1,
2018
    April 2,
2017
 

Risk-free interest rate

     2.2     1.5

Teradyne volatility-historical

     26.8     26.6

NYSE Composite Index volatility-historical

     12.4     13.4

Dividend yield

     0.8     1.0
Fair Value of Stock Options Using Assumptions

The fair value of stock options was estimated using the Black-Scholes option-pricing model with the following assumptions:

 

     For the Three Months
Ended
 
     April 1,
2018
    April 2,
2017
 

Expected life (years)

     5.0       5.0  

Risk-free interest rate

     2.4     2.0

Volatility-historical

     26.4     27.8

Dividend yield

     0.8     1.0